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The Magazine for Sinclair users and Timex/Sinclair users € FA [UK] 


g 


Volume 3, Number 1 


January/February 1983 


Money Management 
Loan Amortization 


Checkbooks 
Keeping Time 


INTERP 
CHRS, EDIT, LOAD, 
RND, RAND 


As Easy as 2+ 2 
a 


UHF Modulator 
EPROM Programmer 


Starblasters 
Space Crisis 
Mastermind 


Forest Treasure 


Ken Uston on Vu-Calc 


O02 
0 
354 


14024°14 


ROM-PAC APPLICATIONS HAS 
PROGRAMS ON PLUG-ON ROM 
CARTRIDGES FOR THE ZX-81 


_ *EDUCATIONAL PROGRAMS 
“APPLICATIONS 
 *GAMES 


Call or Write For Your 
FREE 
Information Package Including: 
*Current list of products and prices 
*Operating instructions for all products 

“Sample applications 
*Adds you to our mailing list to receive new product news 
| *Updates on using the Sinclair with and without our products | 


CALL 404-921-4471 
OR WRITE 


ROM-PAC APPLICATIONS 
5921-A Alhambra 
Norcross, Georgia 30093 


Due to possible trademark infringement Sinclair Applications is now operating under the name of Rom-Pac Applications. 
Neither Sinclair Applications nor Rom-Pac Applications has or have had any connections with Sinclair Research Ltd. 


ell keep 
your Sinclair summing: 


x EC | B EN EME 


nd i: 
SHIFT 


OUR $14.95 SINCLAIR AND TIMEX OWNER-PROTECTION SERVICE PLAN 
WILL SAVE YOU MONEY. 


Timex too! 

Typical repair charges for a 
Sinclair ZX81 can run from $25 or 
$50 up to the replacement cost of 
the unit. So why take chances? 
MicroSync will guarantee unlimited 
service for one year, parts included, 
at one low price. With return postage 


We have the experience it takes. 
We have the parts on hand. 

So act now! If your unit is less 
than 90 days old you can purchase 
our Owner-Protection Service Plan 
for only $14.95. 


pe P= mes am mme wmm mma am m etalon 


Mail To: MicroSync 


and handling paid. Plus our VIP E manors =. i 
treatment for fast turnaround. i Please send Maintenance Agreements for E 
MicroSync’s experienced J the equipment listed below: e 
technicians are ready to service | ZX81 or Timex/Sinclair 1000 i 
your ZX81 or Timex/Sinclair 1000 Less than 90 days old 
i (include proof of purchase) ........ $14.95 ea. i 
with factory replacement parts. We'll Over 90 days old..............05. $34.95 ea. 
return it promptly, and we'll quality- | 16k RAM { 
; : Less than 90 days old 
check your unit before it leaves our : : ‘ ; i (include proof of purchase) ........ $12.95 ea. i 
anice conter MicroSync is THE Sinclair | Over 90days oid... $29.95 ea. J 
authorized Service Center. ; j Total Enclosed.......... U.S. $ l 
We made over 10,000 Your Sinclair computer is a pee ace 
Sinclairs tick last year. remarkable assembly of electronic Í d 
Sinclair equipment has a great components, some unique to E i eneck Cime CIVISA l 
reputation for reliability. But almost Sinclair technology. Our Sinclair | cara# Ex: l 
all computer equipment requires personnel have been trained on, and || Name i 
service at one time or another. -service only Sinclairs. Address 7 
We've been repairing Sinclairs ever Cy. 2 See Zip J 
since their first glitch. . ee eee 


MicroSyn 
The fine print. MicroSync’s Maintenance Agreement covers all parts and service for 12 months IC Q : y C 


after the expiration of original warranty. For units over 90 days old, coverage is for 12 months 

from the date of the Maintenance Agreement. Kits or modified units may require a surcharge. AUTHORIZED SINCLAIR SERVICE 
MicroSync may not repair units damaged by abuse or negligence. Liability extends to repair or 

replacement only. 


4 


SEND CHECK OR Mi 
Income Ta. 


Home Budget 


ashe 


Compatability 14.95 = WriteForFREE@atalogue 9 7 oan 


The Magazine for Sinclair users and Timex/Sinclair users 


— | | n 


Developing an interactive interpreter 


Staff 

Eounder/bditorin- Chief: Ai ws. ek Sod Su Bee a David Ahl 

Manap me ERTOn o Sins aR A ce aed pe 9 Paul Grosjean 

Coatenurne BOMer An fo Ske ed et Jee es David Ornstein 

U.K. Correspondent...........................Martin Wren-Hilton 

CCM a Ke he IO Brig ate ain ohn ha, ree Patrick Calkins 
Assistant Art Director ooh eos BI Diana Negri Rudio | 

RRO MOUS 05.5 5S Ea Poe lg R Reads CS a Rk RS Karen Brown 

Renea Cole 

Operatons Manafer.. o e a A ee so A William L. Baumann 

Personnel and Finance..........................-Patricia Kennelly 

FOE DE A A E a ES ET S ATER AT oe 2 Frances Miskovich 

Carol Vita 

Advertising Sales Manager... e 2. 2... 26-3 0S Bae ee aie Karen Musmeci 

MEMBER 


January/February 1983 


January/February 1983 Volume 3, Number 1 
DEPARTMENTS 48 The Unprintable Characters.................... Schultz 
PEN SE Oh Rains wa UE Ry Seer eRe me Pe Using CHR$ 
11 RAE WANN A Grosjean, Dewhurst, Neng 50 ne tea wie the LOAD Command. ........ .Gentilcore 
12 SYNC Notes... Grosjean 54 Saving Your Fingers... .... Ryan 
15 SYNC Program Listings. ............. auae Using EDIT 
16 JustforFun........ Boyer, Dewhurst, Hampson, Maloff 56 Monna mith Randomness. TERI a .Duguid 
n n ; 
92 Letter fromEngland..........................85 Adams chi sain a as nS Meee eee 
Recent products MACHINE LANGUAGE 
86 HardwareTips......................... Keeney, Turner GA Metis E TE es ee Doakes 
Be Monacor.. oe A ee OS, Beginner's machine language series, part 1 
104 Index to Advertisers.................0 00. c cece eens 70 Machine Code Keyboard Scanning............. Belman 
Read your keyboard 
SYNC IN THE HOME OFFICE HARDWARE 
20 A Personal Money Management Program. ..... Pattison 72 Installing a UHF Modulator.................... Glidden 
Income, expenses, cash flow, comparisons Switching to Channel 33 
27 Checkbook Management...................... Repicky 76 A Cheap and Simple EPROM Programmer. ...... Schaaf 
Updating, balancing, reconciling Add permanent routines to your computer 
30 A Loan Amortization Program.................... Hoag 
Calculate payment schedules GAMES 
32 Keeping Time in the Home Office.............. Dawson 99 Starblasters................. uaaa aana Tandberg 
Calendars, clocks--hands and digital An ion beam defense 
36 Calculating the Days........................... Paludin 102 8K ROM Updates...................... Fowkes, Frahm 
How many days between dates Hangman, Mastermind, Defuse, Forest Treasure 
38 Tidying Up Your Display....................... Godwin 
Put dollars and cents in columns 94 QSAVE REVIEWS ee 
39 Multisave.................. cc cece cece cece e ees Watsons or ee echoes Lewy Fs Sin eRe eee en 
Preserve your records in duplicate or more Software/hardware package review 
40 Making Backups for Machine Language Tapes... Ryan 96 The Stock Market Calculator.................... Daniel 
: Bypassing SAVE Software review 
98 2ZXDataFinder...................... 0. cece eee Cripps 
PROGRAMMING TIPS AND TECHNIQUES Software review 
43 INTERP—The Kernel of Interactive Nuts........... Auer SOO Wile 4 se ERE ee ae Uston 


Business software package 


RE SRA A RE AISI a SE APES TEATS SS AS LE TELE SLE TT TTL SEE NL TIE ODE AE DS LL EE LE EE EE 


Volume 3, Number 1 


SYNC (USPS: 585-490; ISSN: 0279-5701) is published bi-monthly by 
Ahl Computing, Inc., a subsidiary of Ziff-Davis Publishing Company. 
David Ahl, President; Elizabeth B. Staples, Vice-President; Selwyn 
Taubman, Treasurer; Bertram A. Abrams, Secretary. 39 E. Hanover 
Ave., Morris Plains, NJ 07950. Second class postage paid at New York, 
NY 10001 and at additional mailing offices. 

Subscription rates: USA: One year (6 issues), $16; two years (12 issues), 
$30; three years (18 issues), $42. Canada: $3 per year additional. Other 
foreign: $5 per year additional. 

For SYNC advertising information, contact Karen Musmeci, SYNC 
Advertising Sales Manager, Ziff-Davis Publishing Company, One Park 
Ave., New York, NY 10016 (phone: 212/725-4216). 

All other correspondence should be addressed to: SYNC, 39 E. Hanover 
Ave., Morris Plains, NJ 07950. In U.K. to: SYNC, 27 Andrew Close, Stoke 
Golding, Nuneaton CV13 6EL. 

Postmaster: Send address changes to: SYNC, PO Box 789-M, Morris- 
town, NJ 07960. 


letters 


Help Wanted 


Dear Editor: 

I need some help with a MicroAce. 
The K inside the cursor keeps rolling and 
the unit will not respond to keyboard 
commands. I have attempted to trouble- 
shoot it by chip substitution with no luck 
so far. 

Peter Beck 
54 Richwood PI. 
Denville, NJ 07834 


Dear Editor: 

I have noticed that saving programs on 
cassette from my ZX81 results in some 
buzzing sound which is recorded at the 
beginning and end of programs. Exper- 
ience shows that this causes some prob- 
lems when reloading the programs. 

Is there any way or any hardware mod- 
ification that will get rid of this buzz? 

Ho Tiap Fen 

PO Box 209 

Bandar Seri Begawan 
Brunei 


New Product Problems 


Dear Editor: 

My first computer was, and still is, a 2K 
MicroAce. Now with the vast (relatively 
speaking) amount of peripherals available 
for the ZX81, I am seriously considering 
upgrading it significantly. 

The problem, however, is that many of 
the ads in SYNC do not indicate whether 
or not the products are compatible even 
with the ZX80, let alone the MicroAce, 
even though they are all essentially the 
same machine with various internal dif- 
ferences. I realize that I will have to install 
an 8K ROM. 


4 


Please publish an article indicating what 
peripherals are directly compatible and 
what modifications can be done to adapt 
those not interchangeable between the 
ZX81 and the ZX80/MicroAce. 

William E. Allen 
2912 Metairie Ct., Apt. 24 
Metairie, LA 70002 


Ed.—Since the number of ZX8ls out 
there is significantly more than the ZX80 
type, most advertisers are naturally aiming 
at the larger market. If a ZX80 or 
MicroAce owner sees a peripheral or pro- 
gram of possible use, the best bet would 
be to contact the advertiser directly find 
out whether that product is compatible. 
We would welcome seeing an article pro- 
viding the kind of analysis suggested. 


Dear Editor: 

Congratulations! It is good to see that 
someone has a magazine devoted to the 
Sinclair line of computers. Before I buy a 
computer though I want to know if it has 
programs to do what I want it to do. Do 
you know or can you find out if there are 
programs for: speed reading, analyze and 
predict the stock market performance of 
any particular stock, an electronic circuit 
designer, analyze and predict the winner 
of a horse race, and a program gener- 
ator? 

I need someone to give an impartial 
view. Can you? 

Carlos Urrutia 
RR4, Box 5A 
Gregory, SD 57533 


Ed. — Your best source of information on 
programs is our ad pages. Each issue 
brings new products as well as continued 


offerings of previous products. Through 
our reviewers we try to give a fair evalua- 
tion of products and programs. However, 
we have not run any reviews comparing 
programs for the Sinclair computer series 
with similar programs for other computers 
except perhaps as a point of reference. 
Help is on the way, though, because we 
are planning to publish a comprehensive 
buyer's guide for products for the Sinclair 
and Timex/Sinclair computers. See 
SYNC Notes in this issue for further 
details. 


Dear Editor: 

As the ZX81 becomes more popular, 
hardware and sofware from different ven- 
dors is flooding the market. Many per- 
form the same function or offer the same 
type of software. 

How is the average consumer supposed 
to know which product is best for his 
applications and which is the better buy if 
there is no information available? 

In the near future does SYNC plan to 
give honest, in-depth reviews on all new 
products for the Sinclair machines? 
Sheree Draft 
1171 Boylston St. 

Boston, MA 02215 


Ed. — We cannot review all new products; 
there are just too many. This is why we 
have invited reviews from users who have 
had extended experience with a given 
product and why we prefer comparative 
reviews whenever possible. We also 
expect such reviews to be honest and in- 
depth. The increase in space devoted to 
reviews will provide more extended pro- 
duct information. 3 


Dear Editor: 

In an age when merchandisers often 
are thought of as rip-off experts, I would 
like to salute one of your advertisers. 


SYNC Magazine 


Britain’s leading Software house means VJ LN 


li 


I | Il 


Iiiih 


| 


il 


| 


ee 
sel and the Beast__ 


of Gnomes 


Tilia, ' 


Il 


rot 


When it comes to fast service, prompt 
replacement, and helpful information, 
Peak Software of San Carlos, CA, rates at 
the top of my list. 

A goodsized segment of any industry 
could take customer relations lessons 
from David Farrell of Peak. 

Robert J. McGarvey 
28 Raleigh Rd. 
Kendal Park, NJ 08824 


Elimination 


Dear Editor: 

The Elimination Game in SYNC 2:5 
can be used by unexpanded Z X81 users 
with a few changes. The original program 
uses a numeric array which requires over 
50 bytes to store and a FOR-NEXT loop 
to print. The change uses strings to store 
the numbers (1 byte per character) instead 
of the array (5 bytes per character). 
Strings are ideal for storing numerical 
data from 0 to 9 because they are com- 
- pletely flexible in length and PRINT much 
faster. 


The rules of the game are the same 
except that to terminate the game after a 
loss 0 is entered. Any other invalid num- 
ber will begin the turnover from the roll. 
If more than one number is required to 
complete the roll, a total is given. 

By the way, I am in the process of 
learning machine language, and, although 


I have a ZX81, I would like my machine ` 


code programs to run flicker-free on an 
8K ZX80. Isn’t there a subroutine in the 
ROM to display a frame to the TV? 
Michael B. Williams 


1300 DePaul Way 
Virginia Beach, VA 23464 
10 RAND 
20 LET A$=“ 1 2345678 3° 
30 LET R= INT (6#RND}+INT (GERN 
Pit 
49 LET T=8 
50 LET B$=A4 
5@ CLS 
72 PRINT “NUMBERS TO ELIMINATE 


6@ PRINT AT 4.0; “ROLL Toae 

90 PRINT AT 2,0: B$; 
i890 INPUT N 

IF NOT N THEN RUN 
IF SeS {N-53 >4 THEN GOTO 4c 
130 IF &6S€iN+N} (OSTRE N OR NOT G 
SDE BANAN? SEN GOTO 4G 


148 LET T=f+ 
150 IF T>R THEN GOTO 46 
“TOTAL “iT 


168 LET BS(N+tN) = 

170 PRINT AT 4.21: 

180 IF T:R THEN GOTO 90 
ET &¢=6¢ 


So 
2183 PRINT AT ®©. Oi “WINNERES2242¢ 
FXXEREEE" 


ZXPRESS™ — 


Elimination in 1K 

Type in the program, hit RUN and 
ENTER. 

The numbers 1 to 9 will appear with a 
number representing a dice roll. Choose 
which number or numbers you wish to 
eliminate. Your choices must equal the 
number rolled. The object of the game is 
to eliminate all the numbers. When the 
end of the game is approaching, a roll 
higher than the total left in the display 
will end the game. The lowest number 
wins. To play again hit ENTER. 


DEF and PAUSE 


Dear Editor: 

The article on DEF in SYNC 2:4 was 
very informative, especially for one using 
programs involving many repetitious 
mathematical expressions. However, the 
two programs used to demonstrate the 
use of A$ and F$(X) with VAL were too 
slow even in FAST. I would suggest a 
better program to illustrate the simulation 
of DEF FNA(X) on the ZX81. 

Furthermore, if line 190 were written 
PRINT AT 23,10;F$(B), there would have 
been space on the bottom of the screen 


Non-Trivial Solutions’ new Integer Basic Compiler! Now you can write 


programs in rapid time! 


e compiles ZX-81 Basic source code to machine language: write and debug 
in a subset of ZX-81 Basic: compile when it’s right 


increases the speed of the ZX-81 20 to 50 times 


208 regular variables, 26 dimensioned variables; variables are 16 bit 
two’s complement integers 


compiled code can be stored in REM or in 2000H to 3FFFH address 


segment, if available 


the source code can be located anywhere and the position of the com- 
piled code can be selected, allowing you to write a long program, com- 
it in pieces, and link the pieces 


4 functions -- 


14 key words 
16K or more RAM 
$29.95 


Still available: 


PEEK, RND, USR, IN KEY$ 


e Letter Raiders & Life with Palette 
e challenging games 


e $9.95 each 


(Copyright 1982 NON-TRIVIAL Solutions) 


ZXPRESS 


Life with Palette 


CJ Check enclosed Charge my O Mastercharge O Visa 


Card No. 
Signature 


ea | 
NON-TRIVIAL SOLUTIONS 


QUANTITY 
ae) 
ee 
comes 

Exp. Date 


P.O. Box 2941 
Amarillo, Texas 79105 
(806) 376-5723 


SYNC Magazine 


If you own a Timex-Sinclair 1000 or 
ZX81 computer, you should have a 
Memopak behind it. From increased 
memory to high resolution graphics, 
Memotech has a Memopak to boost your 
system’s capabilities. Every Memopak 
peripheral comes in a black anodised 
aluminum case and is designed to fit 
together in “piggy back” fashion to enable 
you to continue to add on and still keep an 


integrated system look. 


Printer on t RAM 


High Resolution Graphics 


Order at no risk 

All Memotech products carry our 10 
day money back guarantee. If you’re not 
completely satisfied, return it in ten days 
and we will give you a full refund. 
And every Memotech product comes with a 
six month warranty. Should anything be 
defective with your Memopak, return it to 
us and we will repair or replace it free of 
charge. Dealer inquiries welcome. To order 
any Memotech product call our toll-free 
number 800/662-0949 or use the order 
coupon. 


CORPORATION 


7550 West Yale Avenue 
Denver, Colorado 80227 
(303) 986-1516 
‘TWX 910-320-2917 


IS A MEMOPAK 


——— eee a a a 


tech Corporation, 7550 West Yale Ave., Denver, CO 80227 ı 


ee 


Code: SYCO-1-2 *Price Oty Total l 
| 64K RAM $179.95 | 
l 32K RAM 109.95 
| 16K RAM 59.95 | 
| Centronics Parallel Printer Interface 104.95 . 
| RS232 Printer Interface 139.95 i 
High Resolution Graphics 144.95 
| Shipping and handling 4.95 $4.95 | 
| All prices quoted in U.S. dollars Tax** l 

** Colorado residents please add sales tax Total | 
CO Check (J MasterCard (J Visa | 
i Account No. Exp. 
i | 
: Name i 
| Address 
iy State Zip | 


BEHIND EVERY 
GOOD SINCLAIR 


Memopak 64K RAM The 64K RAM extends the 
memory of your Sinclair by 56K to a full 64K. It 
is directly addressable, user transparent, is 
neither switched nor paged and accepts such 
BASIC commands as 10 DIM A (9000). The 
Memopak 64K turns your Sinclair into a 
powerful computer suitable for business, 
recreational and educational use. No additional 
power supply is required. 


Memopak 32K RAM The 32K RAM Memopak 
offers your Sinclair a full 32K of directly 
addressable RAM. Like the 64K Memopak, it is 
neither switched nor paged and enables you to 
execute sophisticated programs and store large 
data bases. It is also fully compatible with 
Sinclair’s or Memotech’s 16K RAM to give you a 
full 48K of RAM. 


Memopak 16K RAM The Memopak 16K RAM 
provides an economical way to increase the 
capabilities of your Sinclair. And at the same 
time, it enables you to continue to add on other 
features with its “piggy back” connectors. It is 
compatible with the Sinclair 16K or a second 
Memopak 16K or Memopak 32K to give 32K or 
48K of RAM respectively. 


Memopak High Resolution Graphics The 
Memopak HRG contains a 2K EPROM monitor 
and is fully programmable for high resolution 
graphics. The HRG provides for up to 192 by 248 
pixel resolution. 


Memopak Printer Interface The Memopak 
Centronics Parallel or RS232 Interface 

paks enable your Sinclair to use a wide range of 
compatible printers (major manufacturers’ 
printers available through Memotech at 
significant savings). The resident software in the 
units gives the ASCII set of characters. Both 
Memopak printer interfaces provide lower case 
character capabilities. The RS232 Interface is 
also compatible with modems. 


New products coming soon Memotech will 
soon be introducing four new Sinclair 
compatible products: a high quality, direct 
connection keyboard, a digitizing tablet, a 16K 
EPROM and a disk drive. Watch for our future 
advertisements. 


TIMEX/SINCLAIR 1000 or SINCLAIR ZX-81 Software 


data~asette 


DATA-ASSETTE brings you proven software 
from around the world. We are the agents 
for some of the best software produced 

for these machines and have several 

of our own developments. 


We have over 60 programs of software in our catalog and feature a 
range of challenges, games, adventures, business, personal or 
home tapes. If you don’t see something you like, then just send 
$2.50 for post and handling, and we will credit you the money 
against your first order. Call for more details. 


Information and product spec sheets may be obtained by mail, or 
phone our HOT LINE 800-523-2909; in Penna 215-932-4807. 


Business or home: These are most efficient and user 

friendly. Special feature allow variable size RAM packs (16, 32, 48, 
64) to be used and save or load through the ZX-99 is standard 
option. 


PROPERTY MANAGER (16K) 

BUSINESS or PERSONAL FINANCIAL $24.95 

Our accountant believes that this program allows your system to be 
tax deductible as an individual, we will advise upon further notice. 


Property owners or Managers will find this an extremely valuable 
tool. Provides for any combination of 10 units in 2 buildings or 2 
units in 5 buildings per program. If you have more than 10 then just 
run a new copy of the master file. The program tracks each unit for 
RENT, up to 15 variable expense categories, and 15 fixed expense 
lines, all for a full year. That’s right 12 months of data including late 
payments, and optional save routines for the ZX-99. 


CASH FLOW FORECASTER and 

BUDGET ANALYSIS (16K) 

HOME or BUSINESS $19.95 

Brand new financial utility for use at home or in the office. Keeps 
detailed records for twelve months in the three major categories. 
INCOME, FIXED and VARIABLE EXPENSES PLUS LOAN BALANCE OR 
LINE OF CREDIT. Provides the user with the ability to forecast or 
track the history of his cash flow. 


INVENTORY CONTROL AND STOCK ANALYSIS (16K) 

HOME or BUSINESS $19.95 

The first in a series. This program operates as a stand alone control 
or it will operate with the ZX-99 Tape control system for file han- 
dling. Features include stock control of units and of values, with 
separate routines for receipts and returns or sales and shipments. 
Special routine for adjustments in units or values. Program uses 
average cost for inventory value and shipments. Allows the user to 
SORT by code or alpha name. Quick access to stock levels. New fea- 
ture will allow the user to automatically expand the files for 32 or 
65K ram packs. 


MICROMEGA This software is unique for its use of MACHINE CODE 
and handling of complex routines for BUSINESS or HOME. 


COMP-U-SHARE (16K) 

PERSONAL HOME FINANCE $24.95 . 
Excellent program that allows the user to maintain an up to date 
record of his portfolio. Stocks, Bonds, Funds or other financial 
investments. Developed by a professional for his own use. Monitor 
your results or run a forecast of expected results. Includes P/E 
ratios, dividends, etc. User guide included. 


CHALLENGE | (1K) $9.95. Four different tests of your skill. Start out 
driving arace and finish up in a war. 

CHALLENGE II (1K) $9.95. Four different arcade style challenges. You 
will be quickly overcome by the desire to win! Both of these are 
written in machine code so that the speed and response are UNBE- 
LIEVEABLE for TS/1000. 

“BANK” (16K) HOME or BUSINESS $14.95. Excellent program for use 
at home or in a small business. Monthly statements reconciliation 
are now an easy task. File structure allows search by item or type 
of expenditure. 


KAYDE ELECTRONICS Hi-resolution graphics at its best. 


$19.95 ea. or $49.95 pack; 16K graphics are only possible with our 
HI-RES GRAPHICS ROM (see page two). We offer three different 
types to illustrate the power of the ROM and the effect on the screen. 
Special introductory offer, buy one and order the ROM and save 
$10.00. 


The three are: PECKMAN our version of the game with real Graphics. 
SPACE INVADERS cannot be compared to the others. 

CENTIPEDE Quoted to be the “BEST MOVING GRAPHIC GAME ON THE 
rh Re 


ROULETTE (16K) $14.95.Accepts all legal bets in any combination, 
one or two players, both against the computer. 


RAMPAGE (16K) $19.95. Not your normal challenge. You play inside 
the RAM and against the memory. Like TRON with GRAPHICS. 


TIME BANDITS (16K) $19.95. Journey through time and space, slip in 
the hole, fight Napolean’s army, raise TITANIC and more. 


ZX/TS DOT MAN (16K) $19.95. Fantastic recreation of the arcade 
game. FAST MOVING and requires lots of skill. Don’t miss it. 


AIRLINE (16K) $14.95. Business game not an arcade game. Chal- 
lenges your financial and logic senses. Be better than SIR FREDIE 
LAKER.... 


RESTAURANT (16K) $9.95. Another business game...Everyone else in 
this business! Can you succeed? Watch out for inflation, plan and 
more. 


with a full selection of accessories 
for the TIMEX/SINCLAIR 1000 
or SINCLAIR ZX-81. 


RAM PACKS All possible combinations are now available. Expand as 
your need change, or simply start with our 64K ram that gives the 
largest possible memory for the price. 


16K Budget model $44.95. SAVE $5.00 off the normal price. Supplied 
without case. No other difference. Full guarantee. 

16K RAM pack $49.95. Selected from major European supplier. Fully 
cased. 

48K Now available with our 32K “Piggy-Back” and a 16K daisy 
chained together. Order both together and save. 

32K “Piggy-back” $109.95. 48K PACKAGE (16K + 32K) $139.95. 

16K Stand-alone $55.95. 

16K Add-on later $44.95. 16K and its UP-GRADABLE to 32K later 
“SPECIAL NEW DESIGN”. Allows upgrade to our 32K by the addition 
of asimple plug-in module. Expand at any time. 

32K Ram Pack Stand-alone $99.95. Closed back or 32K “Piggy-Back 
model (see 48K) UP-GRADE your unit to a full 32K from the start. 
64K Ram Pack $149.95. Massive memory available from the start. 
Uses latest in Chip technology. 


INTERFACES—PRINTERS, COMPUTER TO COMPUTER, AND CASSETTE 
RECORDERS. Now the TIMEX or Sinclair comes of age. Simply by 
adding any or all of these products your unit can grow to the size of 
a mini-computer or sophisticated WORD PROCESSOR. Never before 
has so much been possible with such a small investment. 


ZX-99 Automatic tape control (Up to 4 units) and RS 232 C Printer 
interface. Allows maximum use of the computer. Several built in 
USR commands provide program control over the cassette record- 
anne super features such as “Tape or Tape Copy” or Program list. 
149.95. 
ZX-98 Parallel and Serial Interface all on the same board for $99.95. 
Use one or both to enhance the capability of your computer. Make it 
into a terminal for ON-LINE services or use it to communicate to 
another computer or interface with any printer with a parallel or 
serial port. Several unique features are included to assist the user, 
LLIST, LPRINT and COPY are still operational. Others, for example, 
allow MEMORY EXAMINATION of HEX BYTE. Honestly there are too 
many features to list here, but a better value for your money would 
be hard to find. 
ZX-21 Metered Cassette to computer loading interface. $19.95. Now 
reduce program load errors to a minimum by pre-setting your tape 
recorder to the level that is compatible with the computer. This unit 
has been designed by the leading expert in this field. See our soft- 
ware section for more information. 
ZX-22 Power Driven Cassette Loading Interface $39.95. This unit uses 
the power pack energy to test the Sound of your recorder and gives 
a red or green signal to indicate the proper setting for the computer. 
A bargain if you are troubled by the combination of cassette 
recorder difficulties or computer idiosyncracies. 


CASSETTE RECORDER PACKAGE All in one for $30.00. Package devel- 
oped by Mike Salem, the leading expert on cassette recorders for 
microcomputers. Package includes “THE MICROCOMPUTER USERS 
BOOK OF TAPE RECORDING” a well written 60 page description of the 
HOW and WHY of recording and recorders. A must by itself. Plus a 
specially recorded test tape that allows precise tuning of your tape 
recorder. And finally we will include the Cassette loading interface 
normally $19.95, a value for this very low introductory price. If 
ordered individually they are $6.25 for the book and $9.95 for the 
test tape. 


Get over the post-Christmas blues 


All products are in stock and can be shipped the same day 
for credit card orders. 


KEYBOARDS All possible sizes and features. Selected from the best 
English suppliers with over two years of satisfied customers behind 
them. Select the one that best fits your needs. 


KLIK This unit is the same size as your TIMEX or SINCLAIR compu- 
ter. Forty Keys and multi-colored key labels are provided. Allows 
the user to maintain portability and compactness. Full movement 
and response. “KLIK” is user installable or mail in your unit and we 
will install it for you. $75.00. Please add $1.00 for postage and han- 
dling of the conversion if mailed to us. 


KAYDE FULL SIZE This unit is standard size with the added feature of 
a repeat button. Typewriter touch and feel. User installable $75.00. 
Please add $10.00 and return to us for modification if desired. 


KLIK-2 Same as above but with the extra feature of automatic repeat 
on each key. Just add the new module and the KLIK can be up- 
graded to have this super feature. Can be added to all previous KLIK 
keyboards from Kempston. Special introductory price of $15.00, but 
only $10.00 if ordered together. 


NEW PRODUCT: High resolution graphics are now available. Kayde 
has designed the solution to the ZX-81 or the TS 1000. Fits inside the 
computer and replaces the ROM with graphics of 450 different 
types. PLUS the unit has space for 4K of user on board ROM or addi- 
tional 2K of RAM. $59.95. See our software section for three sepa- 
rate choices of program tapes that use these unique features. 


PRODUCT UNIT TOTAL 
——_|—___+—_+_— 
Pari a e ie Vp ee ea 
pees Ee Se Ve or ren Oy 
pee ee ee ee 
ee ea a ed es ie” 
TOTAL ORDER 

PLEASE RUSH MY ORDER TO: 
Name 

_ Address BENE tees 
City Stale oe Seep 


Charge To: VISA LI Master L] 
Account Number 

Expiration Date 

Signature 


Data-Assette (sy-4] 
56 South 3rd St. 
Oxford, Pa. 19363 


data~asrette 


Reg. $14.95 - Now only $11.20 


(through Feb. 28, 1983 


Learning Timex Sinclair BASIC, Dr. David Lien’s new, 350-page, 
comprehensive manual for the Timex Sinclair 1000 and Sinclair 
ZX80/ZX81, is being offered at a one-time-only 25% pre-publi- 
cation discount through Feb. 28, 1983. 


Dr. Lien’s easy-to-follow style is designed to help those with no 
prior computer knowledge enjoy full use of the Timex Sinclair. 
Each programming step is explained clearly and completely, 
and special Question & Answer sections are included at the end 
of many chapters to test the reader on important points. 


Learning Timex Sinclair BASIC’s simple, step-by-step instructions 
make it ideal for the classroom. And it’s a must for all Timex 
Sinclair owners, especially first-time computer users. Don’t miss 
this opportunity to learn from a proven teacher of BASIC how to 
write your own custom software. 


This is a one-time offer and will not be repeated, so order now. 
Fill out the coupon or call our 24-hour order line at 800-854-6505: 
in California call 619-588-0996 (8:00 a.m. - 5:00 p.m.) 


30-Day Money Back Guarantee 

If you’re not totally satisfied with this book for any reason, 
return it to CompuSoft in salable condition within 

30 days fora full refund. 


Er 


CompuSoft® Publishing 
P.O. Box 19669 

Dept. #070183 

San Diego, CA 92119 


Timex Sinciale 1000 
imex Sinclair 
Sinclair ZX80/ZX 81 


DISCOUNT 


ee ee ee ee ee ee E E 


Please send copies of Learning Timex BASIC at i 
$11.20 each. Reg. $14.95 (Calif. residents add 6%), plus 
$1.65 shipping and handling per book within the U.S. 
Foreign orders, include $2.50 surface shipping and 
handling per book. 


Total Enclosed 


E 

a 

i 

E 

J 

f Name 

I Address 

è City/State/Zip 

- O Check O Visa O MasterCard 
4 
c 
i 


EES ed 


Siana oe ee Expiration Date 
Shipping to begin Feb. 28, please allow 4 to 6 weeks for 


delivery. 
Cle a an an a a aa aa a aa a n n a n n n n 


Special Pre-Publication Offer 


by David A. Lien 


Letters, continued 


for a REPORT or CURSOR and the run 
could have been stopped any time by 
hitting BREAK as usual. Also, this would 
have eliminated the need for the fancy, 
and limited use of lines 330 to 370. 

Alger Salt in SYNC 2:3 expains why he 
had to take extra steps to get around an 
idiosyncrasy in the Sinclair computer 
when the PAUSE function is used. I 
would suggest avoiding the use of PAUSE 
whenever possible and substituting a con- 
ventional FOR-NEXT loop instead. For 
example: 

FOR N = 1 TO 50 
NEXT N 

PAUSE (at least on my TV screen) has 
another undesirable characteristic. It 
causes the image to jump. This is very 
disturbing in graphics. The do-nothing, 
FOR-NEXT loop does not impart any 
motion to the screen. 

I use PAUSE mostly with, say PAUSE 
40000, to get an indefinite delay in the 
run of a program. Then press any key 
except BREAK to continue. Another plus 
is the fact that the screen does not clear 
first when the program restarts. 

Warren Fricke 
273 Canton St. 


saeu = =— 


“Try This” features short programs to 
show off your computer, impress your 
family and friends, and tickle your imagi- 
nation when SYNC arrives at your place. 
Send your contributions to: Try This, 
SYNC, 39 E. Hanover Ave., Morris Plains, 
NJ 07950. 


4K ROM; 1K RAM 
Enter the following lines: 


1@ PRINT 1; 

29 POKE 16427,14 

Press RUN and NEWLINE. Observe the 
results. When you see the error code, press 
any key except SHIFT, then press RUN and 
NEWLINE again. Can you figure out how 
this works? Our thanks to: 

James Grosjean 

50 Kings Rd. 


8K ROM: 1K RAM 
Enter the following lines: 


10 PRINT ai 
20 GOTO 18 


Put the computer in SLOW mode. Press 
RUN and ENTER. Observe the results. Can 
you figure out how this works? Our thanks to 
The Ultimate Magazine (reprinted with per- 
mission) and: 

Neil Dewhurst 

2 Chesterbrook, Ribchester 

Nr. Preston PR3 3XT 

United Kingdom 


8K ROM; IK RAM 

Enter the following lines. 

S FAST 

1@ FOR A=6 TO 16 STEP .@5 

30 LET R=8sC0S (A) COS (2ER) 

30 PLOT (iS¢(42ReCGS (AIFF. t 
+(4e#R"SIN (A) 3) 

48 NEXT A 

S@ PRINT AT 9.19: “B 


Press RUN and ENTER. Observe the re- 
sults. Our thanks to: 

Neal Neirick 

9105 Hollyberry 


a= 
te 


Depew, NY 14043 = Chatham, NJ 07928 Des Plaines, IL 60016 = 


PROFESSIONAL KEYBOARD 


Timex Sinclair 1000 Sinclair ZX-81 S i N C LAI R OW N E R S 
RCO Technical took a HARD LOOK at 
the cost of SOFTWARE for 16K 

ZX81 & T/S 1000 computers. 


Our findings? We can do BETTER! 


Enter programs and data with accuracy and speed. Individual 
keypads provide needed tactile feedback. Enables touch typ- 
ing. 47 keys, six of which are for future use. Space bar. ZX/TS 
key legends. 


This is a completely assembled keyboard, specificially de- 
signed for ZX/TS computers. It plugs into the ZX/TS in min- 
utes. No soldering required. 


An optional enclosure attractively packages your keyboard and 
will also house the ZX/TS circuit board. All connections 
(power, tape, TV and expansion port for 16K RAM, etc.) are 
easily accessible. 

We are so confident that you wil! enjoy using our professional 
keyboard that we offer an unconditional money back guaran- 
tee. If you are not completely satisfied, simply returr it within 10 
days and receive a full refund. 


Order your keyboard today by sending check or money order 
to: 


*CHECKSTUB— checkbook management program 
with the analytic POWER you need to find out where your 
money is going. Thirty user definable budget categories. In- 
novative displays. 


*EZ-HEX— Hex code utility. Write-edit-test Z80 ma- 
chine language programs in hex code. Excellent program- 
ming aid. Easy to use and FAST. 


*Z-WRYTER— Word processor. Write, edit, and save 
text using powerful editing functions that make writing en- 
joyable. Supports ZX printer. 


*PROFIT PLAN- Profit analysis. Calculates break- 


even point — profit projections using entered fixed & vari- 
able cost data. 


THE FULL SPECTRUM 
3829 Mainsail Circle 
Westlake Village, CA 91361 


$9.95 Each plus $1 shipping 
Send check or M.O. to: 


16K req 


RCO Technical 
P.O. Box 773A 
St. Ann, MO 63074 


Keyboard US$69.95 
Enclosure 29.95 


Shipping/Handling $4.95 
Calif. Res. add 672% tax 


January/February 1983 11 


Sync notes ——eL 


SYNC in the 
Home Office 


Our theme section in this issue is 
“SYNC in the Home Office.” Among the 
reasons for buying a computer is to get a 
tool that will take care of some of the 
drudgery of home record keeping and 
financial calculation. We have had a num- 
ber of requests for such programs, so we 
have gathered several programs that illu- 
strate something of how the Sinclair com- 
puter series can be used at home. In 
addition we have included several pro- 
grams on time calculation, display set up, 
and making and maintaining support 
records. 

This section is not an exhaustive pre- 
sentation, and we hope to see more pro- 
grams developed by our readers for home 
office work. Normally we do not accept 


Paul Grosjean 


programs showing how to use your com- 
puter as a calculator since we assume 
most people have calculators. This does 
not exclude programs which combine a 
series of time consuming steps on a cal- 
culator. In such cases the computer does 
what it is supposed to do, namely, com- 
pute. 

Browsing through the ads and 
Resources Column of this issue and our 
last issue will show quite a variety of 
programs of possible use to the home 
office. If you have used one of these 
products and found it valuable, we hope 
you will write up a short review for us. 
Several reviews of products useful to the 
home office top off the theme emphasis 
of this issue. 

We are planning a “SYNC on the Job” 
theme section for our Mar/Apr issue. 


SYNC Buyer’s Guide 


Issue 

The May/June issue of SYNC will be a 
buyer’s guide issue. We will have some 
regular articles, programs, and reviews, 
but the majority of the content will be a 
directory with short descriptions of all 
known peripherals, add-ons, software 
packages, books, and other products 
related to the Sinclair and Timex/Sinclair 
computers. 

Vendors are invited to submit a product 
description of up to 60 words for each 
product they have available for this com- 
puter series. The description should 
include product name, order number, 
cost, ordering details, ROM and RAM 
requirements, and as complete a product 
description as possible within the 60 
words. Send the descriptions to: 

Buyer’s Guide Issue 

SYNC Magazine 

39 E. Hanover Ave. 

Morris Plains, NJ 07950. 


Get on the Control Bus 
for only $49.95 "ip 


-.. and be on TIME. 


With our real Time Clock and Calendar 


TIME MONTH DATE YEAR DAY OF WEEK 


8 lines departing 


(outputs capable of driving relays) 


8 lines arriving 
(T T L compatible inputs) 


Compatible with ZX8 1/80 


SS5o5o.. 12.95. e OE T 

@ Leap year correction 

@ 12/24 hour format 

@ + 30 second time correction 
(hardware or software) 

@ Battery back-up circuit 


Comes complete with: 


@ All software needed to operate clock and 


Input/Output ports 
@® On board 5 volt regulator. 


@ Feed through Sinclair Bus connector 


to allow normal expansion. 


@ Each port is expandable through Multiplexing. 
® /O ports and other controls mate with Radio Shack“ 


44 pin edge socket. 
@ SO day Warranty 


Accessories used with I/O Board: 
@ ^A to D and D to A converter 


@ Wireless control system compatible with BSR“ 


modules 


@ Solid state 25 amp switch modules 


@® 8 SPDT 5 amp relay card 


Future products used with I/O board: 


@ Touch Tone™ encoder/decoder and 


other telephone products 
@ Speech synthesizer 
@® Sound synthesizer 


MicroAce & TIMEX ™" 1000 
3 All accessories can be connected together 


and separately controlled from the I/O Parts 


Descriptiom 


VO port with real time clock [Built and tested) 
PC board and manual of #310 
A to D and D to A converter (Built and tested) 


Bare Ato D and D to A board and manua! 


Wireless control system (Built and tested) 
Solid State™ AC Switch (Built and tested) 


Clock IC and crystal (Tested) 


Shipping and handling 


Orders accepted by phone or mail 


California residents add 6% tax 


For mail orders, send check or money order 
Foreign orders must be in U.S. currency 


write for free catalog 


SR AUIS 


P.O. Box 3295 
Escondido, CA 92025-0580 


information (619) 741-5132 
24 HOUR ORDER LINE ONLY 
NAT. 800-227-1617 
Calif. Res. 800-772-3545 


Baus 


(No catalog calls please) 


Ask for operator 367 


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suempuct! I8/OS XZ 


KAYDE Electronic Systems 

ZX80/1 $75 90 
ZX KEYBOARD WITH 

REPEAT KEY 


Fully cased keyboard ........ $75.90 
Uncased keyboard....... ..... $55.90 
Keyboard Case................... $21.90 


This is a highly professional keyboard using executive buttons as found on top quality 
computers. It has a repeat key and comes complete in its own luxury case. This is a 
genuine professional keyboard and should not be confused with toy keyboards currently 
available on the market 


KAYDE 16K RAM PACKS 


The 16K RAMPACK simply plugs straight into the user port at the rear of your computer. It is fully 
compatible with all accessories and needs no extra power and therefore it will run quite happily on your 
Sinclair power supply. It does not over-heat and will not lose memory at all. As you may know. some 
makes go down to 11K after being on for a while. 


This 16K RAMPACK is very stable and will not wobble or cause you to lose your programme. It comes 
fully built and tested with a complete money-back Guarantee. 


KAYDE FLEXIBLE RIBBON CONNECTOR 


Stops movement of RAM PACK and other accessories 
(Not needed with a KAYDE RAMPACK) $25. on 


The KAYDE Graphics Board ıs probably our best accessory yet. It fits neatly inside your ZX81. It 

comes complete with a pre-programmed 2K Graphics ROM. This will give nearly 450 extra graphics 

and with the inverse makes a total of over nine hundred. 359 

The KAYDE Graphics Board has facilities for either 2K of RAM (for user definable graphics), 4K of ROM -90 
or our 4K Tool Kit Chips that will be available shortly All the graphics are completely software 

controlled, therefore they can be written into your programmes. Here are a few examples: A full set of 

space invaders — Puckman — Bullets, Bombs — Tanks — Laser Bases and Alien Ships. 

NO EXTRA POWER NEEDED 


KAYDE 16K GRAPHICS BOARD SOFTWARE 


PECKMAN: The only true ZX version of the popular arcade game. $ 
Centipede: “In all | think this is the best presented moving graphics program I've yet seen.” Phil Garratt. 7 1 9 
Interface. 0 


SPACE INVADERS: The best version available anywhere. Graphics software can only be used with a graphics board 


Centipede: “‘In all I think this is the best presented moving graphics program I've yet seen.” Phil Garratt, "770 
Interface. 7 
3D/3D Labyrinth: A Cubit Maze that has corridors which may go left, right, up, down. Peckman (the 0 
ie we EP et Bae BE Se Ge -7 


latest addition in 81 games). 
WHY WAIT TO PAY MORE — ee ae ie ee 


Pi See ZX Keyboards with key $75.90 each 

FAST, IMMEDIATE DELIVERY ma ae $59.90 each 
“Sate VER RES Pie ible ribbon connectors -JU each 

Post to: Dept SY-3 fae aeiee ae a ee 
Kayde Electronic Systems Ltd Please send me... 16K graphics board software $11.90 each 
Please send ME .......... eee cececeeseseeeeecceeseeeeeees 16K 81 software $11.90 each 


The Conge 


Great Yarmouth : r 
Norfolk NR30 1PJ ENGLAND waa 


Tel: 0493 57867 (Dept. SY1) 


Please pay by 
International money order or certified 
cheque for immediate delivery. 


Please add $5 p&p for all hardware and $2 for all software. Please make 
cheques payable to Kayde Electronic Systems Ltd. 


Hace cent meee come cs emi dia “easy coms Sed min ae ce a les ie es eee ed 


Machine Language 
Series 


In this issue we are beginning a series 
of articles by Harry Doakes which will 
give newcomers to computing the benefits 
of machine language programming. Harry 
is no stranger to SYNC readers because 
of his articles “TR$ and LET A$=A$+B$ 
on the ZX80,” “Safe Machine Code 
Routines,” and “Maps and the ZX80/81.” 
If you have specific areas of interest in 
machine language programming, drop us 
a line. 


Sinclair Inquiries and 
Service 


If you need hardware repairs, contact 
Sinclair’s authorized service center: 

MicroSync Services 

162R Marlboro St. 

Keene, NH 03431 
Inquiries concerning repairs (past, pre- 
sent, or future) should be mailed to 


New! 


MicroSync’s Customer Service Depart- 
ment. Please send a stamped addressed 
envelope for additional service informa- 
tion. MicroSync is offering one year main- 
tenance agreements for Sinclair and 
Timex/Sinclair computers. For further 
information contact MicroSync. 

Sinclair Research Ltd. promises a 
prompt reply to customers with technical 
questions, product operating queries, or 
other problems. However, only mail 
inquiries can be answered. So write a 
letter indicating the details of your prob- 
lem to: 

‘Technical Department 

Sinclair Research Ltd. 

4 Sinclair Plaza 

Nashua, NH 03061 


SYNC on the 
Newsstands 


You will be receiving this issue of 
SYNC somewhat earlier than you may 
have expected. The reason for this is that 
we have advanced the publication time 
about a month in order to enter into news- 
stand distribution of SYNC. la" 


AIR TRAFFIC CONTROL 
Cassette software for your 16K 
ZX81 or TS1000 


Meet the challenge of up to 24 aircraft speeding 
across your screen to 5 different destinations! 


No “safe” altitudes - every plane is your responsibil- 
ity. You must identify type, heading and altitude and 
skillfully guide them through crowded airspace, while 


a real-time clock builds the pressure. 


Every game is different. 


Aircraft, ranging from a Cessna 152 to 


SYNC Program Listings 


Before entering the programs in this 
issue, readers should note the following: 

` The ROM and RAM requirements for 
using a given program are shown at the 
top of the first page of the article. Observe 
these carefully. NEWLINE and ENTER 
are used interchangeably. 

A letter after a number shows the type: 
b for binary; d for decimal; h for 
hexadecimal. 

In PRINT statements: 

#: Enter a necessary space. 

A (32): Use the graphic character on 
the A key 32 times. The underline means 
use the graphic on that key. 

A: The overline means use the key in 
inverse. _ : 

INPUT: An underlined word found on 
the keyboard should be entered from the 
keyboard, not spelled out. If the keyword 
will not ENTER, hit THEN, the keyword 
you want, backspace and delete THEN, 
continue entering the line. This memory 
saving technique may be disregarded if 
you have enough RAM. | 


epEECH RECOGNITION 
a E i Raw Sen t a ge? Sigi A 


Hugely successful Speech Recognition System, 


the new Boeing 767, enter your airspace 


whether you are ready or not. 

Over 3K_of machine code means immediate re- ‘INPUT-O 

sponse. Experience the tension as you race to avoid N 
_the controller's nightmare - a mid-air collision! 


Order AIR TRAFFIC CONTROL from: 


Powerplay Systems 
P.O. Box 752, Woodside 
New York, NY 11377 


Send $12.95 plus $1.50 s&h (NY res. add sales tax). 


Allow 3-4 weeks for delivery. 


January/February 1983 


MUSIC 3CHANEL 


CONNECT RE 


TP 
LAY LED. PHOTOCELL etc $49 


SPEECH SYNTHESISER -- MOUTH 


WITH AMPLIFER + SPEAKER $99 


complete with microphone, software and full instructions. 


PROGRAMMABLE 
= TWO 8bit BIDIRECTION PORT 


AUDIOVISION 
Teoh. NORMANDIE AV. CAL = 


HOLLYWOOD 
_C.A. 90027 


213 


6605217 


15 


JUSt FOr Fun Se 


Generally SYNC prefers articles in some depth to help you get more out of your _ 
computer. However, we receive many short programs that illustrate a point, 
demonstrate a technique, or show something the reader has found interesting. 
“Just for Fun” shares these programs with you. If you learn something, great. If 
you have some fun, great. If you have some that you want to share, send them 
to: Just for Fun, SYNC, 39 E. Hanover Ave., Morris Plains, NJ 07950. 


Listing 2. 


Bombsmash a 
Si PRINT AT INT (RND£163 +3. INT 
M. H EE 
. Hampson 40 LET B=@ 


e e LET 5S=8 
In Bombsmash the display shown in 100 PRINT AT 22,15; " 


the sample run passes over your firing 180 PRINT AT 22.15) mim > 
base from right to left. Your base remains 135 LET P=P-2 


LET P=p-— 
i4@ PRINT S&T F256 


stationary. You fire at the moving targets 150 LET N=PEEK (PEEK 16398+256+ 
3393 


by pressing any key. If you hit a part of : Deere Ree ia 
the letters or inverse asterisks, you get | m =E Ea ae 1°09 IF N THEN core aon)” 
one point. Your goal is to wipe out all the | È E B 5 ae BEE see ee 
targets in the display. However, if your -~ SAG LET Boa EI E A E 
shot misses all of the targets and continues {| bombsmash 220 LET B=1 
S00 PRINT AT 1.1; "GAME GUER: YOU 


to the top edge of the display, you lose. 
The program is entered in three steps: 
1) Type in 
1 REM (followed by 32 characters) 


2 
R SCORE+>:3>;3";S 
310 IF INHKEY&<:>CHRs 148 THEN GO 
TO Sok 


4190 LET 5=8 


2) Type in as direct commands the Listing 1. 42@ GOTO 180 
POKEs in Listing 1. 
3) Type in Listing 2. POKE 16514,42 PORE 16529;31 = i 
To play the game press RUN and POKE 16515,12 POKE 16530,0 Space Pirate Attack 
ENTER. You fire by pressing any key. P OKE 16516,64 POKE 16531,237 
Your score will be displayed at the end of POKE 16517,6 POKE 16532,176 Sheldon Maloff 
the game. The highest score is the best. POKE 16518,24 POKE 16533,43 After a very successful mining opera- 
Hit ENTER to start a new game. POKE 16519,197 POKE 16534,58 tion in the asteroid belt, you are on the 
Graphics notes: POKE 16520,35 POKE 16535,33 way back to your base to unload and 
20: A (32); set up display to show as in POKE 16521,126 POKE 16536,64 resupply for the next expedition. Sud- 
the listing; finish off with A(32). POKE 16522,50 POKE 16537,119  denly, you are attacked by a fleet of 
= 31: inverse asterisk. POKE 16523,33 POKE 16538,35 pirates. Although you are outnumbered 
120: 6,W.4. POKE 16524,64 POKE 16539,193 20 to 1, you have a chance because your 
POKE 16525,84 POKE 16540,16 position is such that they cannot attack 
M. Hampson, 7 Hereford Dr., Clitheroe, Lancs POKE 16526,93 POKE 16541,233 Rea OR a er aR eet tein ME Ler OSS SRM 
BB7 1JP, U.K. Reprinted from The Ultimate POKE 16527,35 POKE 16542,201 Sheldon Maloff, 1102-432 Huntsville Cr., N.W., 
Magazine with permission. POKE 16528,1 Calgary, Alberta, Canada T2K 5E1. 


16 SYNC Magazine 


Extend your ZX81 System: 
Add Memory that won't Pen 


ADD YOUR OWN SYSTEM UTILITIES 


~ BUILD UP A LIBRARY OF MACHINE 
LANGUAGE SUBROUTINES 


> UPTO 8K NONVOLATILE RAM ° 
2. 


USE HM6116P CMOS RAM 
OR 2716/2732 EPROM 


wx LOW POWER BACK-UP 


COMPATIBLE WITH “<3 AA 


16K RAM PACKS 7 7 


This memory board is designed to fill the transparent 8K 
block of memory (from 8 to 16K) in a ZX81-16K system. 
The use of HM6116P 2K CMOS RAM memory IC's with 
their own reserve power supply means that routines stored 
in the RAM are nonvolatile — the RAM retains its memory 
even when the ZX81 is switched off or reset. Moreover, be- 
ing RAM, the routines you store in the memory are easily 
modified. 


With this board it's no longer necessary to place your 
machine language routines in REM statements, in string 
variables, or beyond RAMTOP. You can build up a resident 
library of machine utilities for use by your BASIC system. 


wre 


HUNTER, 1630 FOREST HILLS DRIVE, OKEMOS, MICHIGAN 48864 


*or TIMEX 
1000 


$9995 


Complete step-by-step instructions in a 14 page manual 
make assembly of the board easy. Construction takes be- 
tween one and two hours. The kit (pictured above) is com- 
plete with a silkscreened solder-masked printed circuit 
board, all capacitors, resistors, transistors, sockets, con- 
nectors, integrated circuits, and the lithium cell. The board 
is Supplied with one 2K CMOS 6116P-3 RAM — it will ac- 
comodate three more for a total of 8K. 


Send check or money order for $29.95 plus $1.95 shipping 
and handling to the address below. The printed circuit 
board with the instruction manual is available separately 
for $15.00 post paid. 


—_—, 


H 


you simultaneously. It all depends now 
on your skill and a little bit of luck. Your 
defense screen displays the field of attack. 
The radar will locate the pirate ship and 
show its location by displaying a number 
from 0 to 9. To fire you must press the 
corresponding key on your firing control 
console. If you are fast enough, you will 
score a hit. If you press the wrong key or 
do not fire at all, you will miss the pirate. 
In a fraction of a second the next pirate 
will appear on your screen. When all the 
twenty have appeared, the game ends and 
your score is displayed. 

When you have entered the program, 
press RUN and ENTER. The playing grid 
consisting of colons will then appear on 
your screen. As soon as this grid is com- 
plete, the game starts. So be ready. A 
number from 0 to 9 will appear some- 
where on the field. Press the same number 
on the keyboard to fire. 

After the game is over, the field will be 
displayed. The periods represent the 
place where you destroyed a pirate ship. 
The pirates who escaped are shown by 
plus signs. The pirates that you were not 
fast enough to hit or that you did not 
shoot at are shown as numbers. 

The computer randomly selects a time 
between 0.1 and 1.0 seconds when you 


January/February 1983 


press a firing button. The game thus com- 
bines the elements of skill and random- 
ness that a good game must have. 

Graphics notes: 

5: PIRATES (inverse). 

80: X (inverse). 


(RND #20) 
> iX +20? 


58 LET &=CODE INREY$-20 


6S IF @<>-28 THEN L =108 

70 NEXT R 

75 IF @<@ FHEN GOTO 35 

8@ PRINT : 

85 IF xX=8 THEN L 5=5+1 

ae Pa je X,Y” AT Q, Y;a." 


95 NEXT 
100 PRINT AT 10,0; “S=";5 


Space Age Graphics 


Robert G. Boyer 


Keith Comer’s article in SYNC 1:3 on 
graphics intrigued me, so I wanted to use 
it on my ZX80 with the 8K ROM. The 
conversion involved only a few changes 
in the program lines. However, the 4K 


Robert G. Boyer, 1103 Rivlin Rd., Huntsville AL 
35801. 


ADVENTURE 


VOYAGER |-Voyage thru time and space in 
this new fantasy game. In Voyager | you will 
travel to Sangrel to find the rare element Vali- 
um for new Energy Weapons. Voyager | 
includes: 


One key entry of commands 
Over 16 Billion Characters 

2 Sides of Adventure 16k each 
Graphic display of status 

Over 20 Encounters to deal with 
Quality C-20 Cassette 
Instructions Only $9.95 


You may use one of your own Characters from 
your favorite Role Playing Game if you wish or 
you may use one of over 16 billion Characters. 


******* VOYAGER II COMING SOON******* 
Saveable in progress 


Explorer l-You find a strange new world when 
you walk into a strange mist on your way 
home. This is a text adventure and is saveable 
inprogress. $9.95 


Explorer Il-After a week back home once 
again you find yourself transported to a 
strange new world. Text adventure - Saveable 
inprogress $9.95 


Send for catalog with 1k to 16k programs. 
Postage is included in price. All programs 
come on a Quality C-20 Computer grade 
Cassette with instructions. 


Send to: Chris White 
789 S. Green Bay Road 
Lake Forest, IL. 60045 


and 8K ROMs have different codes for 
the characters. To convert a 4K ROM 
picture to the 8K ROM requires getting 
the character equivalents set up. The two 
lists are given in Table 1. If you are going 
to translate a picture, follow this table. 
However, you can start from scratch with 
your own ZX81 or T/S 1000. 

To use the system, turn to “The Char- 
acter Set” chapter in your manual. Put 
the letters A-J beside characters 1-10 and 
M-V beside characters 129-138. The 
inverse space becomes the letter L. 

If you do not have the original article, 
get a sheet of graph paper. Lightly rule 
every other line horizontally and vertically 
so that you will have blocks divided into 
four smaller blocks. Each of the larger 
blocks represents a full character space 
on the computer. Now draw your picture 
by shading the small blocks. You can use 
solid black, grey, and white (by leaving a 
blank). When you are finished, look at 
the larger blocks and note which of the. 
various pixel arrangements in the char- 
acter set looks just like that four block 
unit. Enter the letter for that character 
into your string. Do not forget to indicate 
white spaces. The pound sign (found on 
the shifted space key) indicates the end 
of the line. 


17 


Ņ 


BY TE-BACK modules 
|64-K MEMORY $119.: 


INSTANT INFORMATION 


WITH 
ous BYTE-BACK’S MD-1 


MODEM only $1 19.35 


WIRED and TESTED $149.95 


Use your phone to connect your “LITTLE” ZX81 to the 
“LARGEST” computer networks in the worid. With BYTE- 
BACK’s MD-1 MODEM connected all you do is dial a 
phone number (usually local), press a few keys and watch 
the data appear on your TV screen. (Software is included) 
This MODEM can be used in either the “originate” or 
“answer” mode with selectable baud rate. 


You can have immediate access to: 


UNIVERSITY COMPUTERS,DOW JONES, 
UPI, AND MORE ! 


As an extra bonus an RS-232 port is provided to 


allow you to drive all standard RS-232 peripherals. 


(75 to 9600 Baud) 
BYTE-BACK’S BB-1 


eas ooo MODULE 
$59.00 /n Stock! 


WIRED and TESTED $69 


e 8 Independent Relays 
(with LED status indicators) 

e 8 Independent TTL Inputs 
si Schmitt trigger buffers) 


e By using a single POKE command 
yOu Can change and latch the status 
of each of the 8 relays 


e Your ZX80/1 can read the 
Status of all 8 inputs by the use of a 
single PEEK command. 

e A comprehensive manual: is in- 
cluded that has complete application 
details. 


WIRED and TESTED $129.95 
IN STOCK! 


SAME DAY SHIPMENT! 

WHY PAY MORE? 
BYTE-BACK’S M-64 extends the memory of your ZX81 or 
Timex-Sinclair 1000 to a full 64-K. It's user transparent. It 
plugs directly into the back of the ZX81 and has an 
expansion port to allow you to still use a printer. No extra 
power supply is required. It has all standard features plus 
the area from 8-16-K can be switched dut in 2-K incre- 
ments for memory mapped peripherals, PROMS, etc. 
Same proven reliability as our M-16 with thousands in 
use. 


EXPAND YOUR 16K SYSTEM 
bie $59.95 KIT 


WIRED and TESTED S69 95 


If you have a Sinclair 16K 
RAM module and need more 
memory, expand it to 32K and 
beyond by using BYTE-BACK 
M-16 MEMORY MODULES. 
You can't connect two Sin- 
clair 16K RAM modules together, but you can connect 
one Sinclair 16K and one or more BYTE-BACK 16K 
modules to get all the memory you need. 
THOUSANDS IN USE WITH PROVEN RELIABILITY 
IN STOCK — SAME DAY SHIPMENT 


RS-232 Module $59.95 


WIRED and TESTED $69.95 IN STOCK 
Allows you to connect ZX81 to all RS-232 printers & terminals. 


ALL MODULES CARRY 90-DAY WARRANTY 


TRY BYTE~BACK MODULES FOR 10 DAYS WITH NO OBLIGATION 


Remember with: BYTE-BACK modules you are NOT limited to using only one module at a time! 


Shipping and Handling $4.95 


ORDER PHONE (803) 532-5812 


Exp. Date Card No. 


O M-16 Blank PC Board 
O Modem Kit $119.95 


$149.95 


Bill My O Visa O MasterCard 


Name. 


BYTE-BACK CO. 
Ph. (803) 532-5812 


Address 


LEESVILLE, S.C. 29070 


City/State/Zip 


RT. 3, BOX 147 ¢ BRODIE RD. 


Mail To: BYTE-BACK CO. ¢ Rt. 3, Box 147 © Brodie Rd. è Leesville, S.C. 29070 


You are converting your picture to a 
string which the computer will display as 
a picture using the graphics characters. 
With 16K RAM the possibilities for this 
program are endless. 

Listing 1 gives the program for storing 
and producing your picture. A sample 


Figure 1. Character Sets. 


4K ROM 8K ROM 
2 5 
3 131 
4 1 
J 2 
6 4 
7 135 
8 6 
9 8 
10 9 
11 11 
130 133 
131 3 
132 129 
133 130 
134 132 
135 7 
136 134 
ih Fae 136 
139 138 


Listing 1 


10 LET AG="SSOOCESBDIRESEDIRDES 
MDIBREASSROCOCOOOOCCODES SASSERES 
RO7VESCF LA SRDOSCOCOCCCALSAFSSFCESRE 
SS ga eg 


Cc 
ET X DE A$ 
© IF X=12 THEN PRINT 

IF X=12 THEN GOTO 808 
4 IF X:38 THEN GOTO 119 
50 IF x<46 THE ET X=X-S? 
5S IF X=46 THEN LET X=X+86 
60 IF X>47 THEN LET X=X+79 
70 PRINT CHRE X: 
80 LET AF=ASt2e To 3; 
99 IF As="" THEN GOTO 145 
18@ GOTO 20 
11@ FOR N=1 TO X-25 
120 PRINT “ “i 
138 


NEXT N 
GOTO 8&0 


picture is given in line 10 in the A$ string. 
If you are developing your own picture, 
enter the letters into the A$ string in line 
10. Type in the program, press RUN and 
ENTER. As you may guess when you see 
the picture, I work for NASA. 


Driver 
Neil Dewhurst 


In Driver you are at the wheel of a race 
car on a hazardous race course. This is a 
test of your driving skills. You must avoid 
the obstacles as you speed toward to finish 


Neil Dewhurst, 2 Chesterbrook, Ribchester, Nr. 
Preston, PR3 3XT, U.K. Reprinted from The 
Ultimate Magazine with permission. 


line. The car heads left by itself. Pressing 
any key makes it head the other way. 
Your score is displayed when you crash. 
Pressing any key restarts the game. 

This program uses the graphics capa- 
bilities of the ZX81 to create the screen 
display of a road and the obstacles along 
the way. The SCROLL feature produces 
a moving course. The INKEY$ function 
allows the input of any key for control. 

Graphics notes: 

40: G 

70: H 

To make the game more difficult, 
change line 40 as indicated at the end of 
the listing. 


1@ LET F=16 

2@ LET S= 

50 SCROLL 

4@ PRINT “SE: TAB INT (RND£293 + 
i; “a 2 TRB 20: ar ae 

50 PRINT AT 20.P:; 

60 IF iS7=PEEK (PEEK 16398+256 
*PEEK 16399) THEN GOTO 106 

70 PRINT “WS 


LET S=S+i 
LET P=P+1-—CINKEYS$="") £2 
GOTO 30 
100 PRINT 5 
PAUSE 4E4 
120 GOTO 28 


PRINT “SE: TAB INT (RNDO#12) + 
W“ TRB 20: “ss 


SOFTWARE 


DR. FLOYD 
Psychoanalysis by computer? - well, not 
quite but Dr. Floyd will carry on a conver- 


sation with you using psychoanalytic tech- 


niques giving the appearance of artificial 


intelligence. Requires 16K RAM. $10.95 


GRAPHICS PAC | 
An introduction to Sinclair graphics- 
includes: 2 random picture drawers, allow 
creation of “Pop” art. A screen formatter 
which allows placing any character 
anywhere on the screen. Complex pic- 
tures may be created & saved. Doodler 
allows line art drawings to be created & 
saved. Requires 16K. $10.95 


WORD PLAY 
Includes: “Jargon” - a jargon word 
generator. “Animal” - a fun game where 
the player teaches the computer all about 
animals. “Story” - the computer writes 
stories using the players input names, 
places, etc. Can be very funny for kids. 
“Haiku” - the computer composes HAIKU 
like poetry. Requires 16K. $10.95 


| SNAKES ALIVE 

A group of arcade type snake games. You 
must evade, box in, capture or destroy. 
Fast moving and a lot of fun. Requires 
16K. $12.95 


All software is on high quality cassettes 


and is replacement guaranteed. 


“APROPOS TECHNOLOG 


7X81 - TS1000 


TO ORDER: 


Send Check or Money Order 
For the total plus: 
$3.00 shipping (Software) 
or $4.00 shipping (Hardware) 
Calif. residents add 6% tax. 
Phone orders: CALL 


805/482-3604 


For credit card orders, include all 
information on card. 


350 N. Lantana Ave., Suite 821 œ 


HARDWARE 


SIN16 
S4595 16K RAM 


This RAM plug-in allows the user to run 
virtually all programs written for the ZX81 
or TS1000. Completely assembled & 
tested. The reliable one. 


$4 2595 SUPER SIN64 

64K RAM 
This is the maximum directly address- 
able RAM that your ZX81 or TS1000 can 
use - Memory is used as follows: 0-8K 
Sinclair operating ROM. 8-16K switches in 
or out of use. Used for assembly 
language routines, memory mapped 
peripherals. Contents are safe from NEW 
and cassette (disc) loads thus allowing 
program-to-program communications. 
16-32K BASIC and assembly language 
user program area. 32-64K large data 
arrays & BASIC variables. 


All hardware is completely compatable 
with Sinclair add-on products. Both 
RAMS use the most reliable gold plated, 
bifurcated contact connector on the 
market. 

10 day return privilege on all hardware-90 
day parts and labor warranty-inexpensive 
extended service contract is available- 
WE SERVICE WHAT WE SELL. 


Camarillo, CA 93010 


A Personal 
Money 
Management 
Program 


Alan Pattison 


Where do we stand financially? This is 
one of the questions of greatest concern 
in the home office. We make our depos- 
its, write our checks, and pay our bills, 
but these activities do not provide the 
information we need to interpret our po- 
sition. We need to know not only our in- 
come and outgo, but also where our 
money is and what it is doing. We need 
to know not only this year, but also last 
year and other years. The program be- 
low is one that I developed to provide 
answers to such questions for my own 
situation. You may not have the same 
needs or questions, but perhaps the pro- 
gram will enable you to pose the ques- 
tions you want to your computer and 
find the answers you need. 

When the program has been activated, 
simply enter income, expense, and loan prin- 
cipal items each month. The computer will 
then provide you with: 

1) An income statement for the current 

month and the year-to-date. 

2) An expense statement for the current 
month and the year-to-date. 

3) A balance sheet showing your various 
assets, liabilities, and net worth. 

4) A cash flow statement for the month and 
the year-to-date. 

5) A comparison of expenses to date with 
your yearly budget. 

6) A month by month graph comparing in- 
come with expenses. 

7) Another month by month graph compar- 
ing each month’s expenses this year with 
those of last year. 

8) A listing showing month by month 
income and expenses as well as your av- 

erage monthly income and expenses. 

You can make as many entries as necessary 
for any item—right out of your check book, 
Visa or Master Charge records, etc. Your 
checking account balance and all other assets 
and liabilities will appear correctly on your 


Alan Pattison, 3422 French Loop NW, Olympia, 
WA 98502. 


20 


P E 
EDRF 
a 
em 
nell 
——— 
Since 
——a 


balance sheet. There is also a provision for 
entering transfers of funds between accounts. 

The program works best with your com- 
puter in FAST mode. 

To use the program, each month simply 
enter your income and expenses—typing in 
the name of the item and the amount of the 
transaction. The computer will ask which ac- 


- count the money is for or from, which you 


enter by code “X,” “S,” etc. 

The computer will add together similar 
items and adjust your assets and liabilities 
page, your income and expense totals, your 
cash flow, and your graphs. 

If you have outstanding loans such as a 
mortgage, be sure to enter your principal 
payments under menu item #10. Your interest 
on the loans should be entered on the expense 
statement. 

The program also allows you to enter trans- 
fers of funds between different accounts under 
menu item #10. 


Instructions for Activating the Program 

1) After loading “Money Manager” in your 
ZX81, save the program on tape just as it is in 
case you mess up the rest of the instructions. 

2) GOTO 5 and enter menu item #1. Enter 
an income account name, e.g. “SALARY,” 
enter a zero, then enter another zero. Your 
screen will print the account name, followed 
by “0” under Month and “0” under year. 
Continue entering account names, followed 
by the two zeros until you have entered six. 
(Note: If you want more or less than six 
categories, change the DIM statements in this 
section as well as the FOR/NEXT loops). 

3) Enter “2” and return to menu. Press “2” 
and you will be on the expense sheet. Here, 
you must type in each expense account name, 
followed by “0,” “0,” just as you did with 
income. The program is set up for 17 expense 
items, so, if you want more or less, you will 
need to change the DIM statements and 


FOR/NEXT loops in this expense section. 
With 17 expense items, your screen will dis- 
play a Code 5 at the bottom —press “C” and 
ENTER to continue. 

4) Enter “2” and return to menu. Exit 
the program by entering menu item 12. 

5) Delete all the following statements in 
your listing (simply type each number and 
ENTER, one by one.) 

235, 236, 238, 239, 241, 242, 255, 260, 265, 
319,322, 323, 524, 525, J40, 3214920; 091, 
33273355" 

6) Type GOTO 1700 and ENTER. Your 
screen will show a report code 2. Now type 
GOTO 2500 and ENTER. Your graph format 
will appear on the screen. 

7) Type GOTO 3600 and ENTER. Again 
your screen will show a report code 2. Type 
GOTO 4500 and ENTER. Your income/ 
expense graph format will appear on the 
screen. 

8) Delete the following statements in your 
listing by typing and ENTERing each number 
individually. 

1700, 1720, 1740, 3600, 3610, 3620. 

9) For the 2-Year expense comparison 
graph, you must enter each of last year’s 
monthly expenses. (If you do not do this, this 
graph should be ignored.) Type in the follow- 
ing: 3 

LET R(1)=(January last year expenses) 

LET R(3)=(February last year expenses) 

LET R(5)=(March last year expenses) 
Continue with LET R statements 7, 9, 11, 13, 
15, 17, 19, 21, 23 for the remaining months of 
last year. (Note that these are all odd numbers 
—even numbers are reserved for the current 
year. ) 

Last year’s expense entries will be held in 
reserve and will not appear on the graph until 
the corresponding months this year are en- 
tered. (Except, the graph will show each suc- 
ceeding month’s expenses for last year as well 
as those through the current months.) 


SYNC Magazine 


SOUND withZX-81! 
SOUND with ZX-81! 


MAKE AMAZING SOUND EFFECTS WITH YOUR ZX-81 


a Timex 


= Sinclair 
D 


$49.95 THE ZON X-81 


* The ZON X-81 SOUND UNIT is completely self-contained and espe- 
cially designed for use with the ZX-81. It just plugs in—no dismantl- 
ing or soldering. 

No power pack, batteries, leads or other extras. 

Manual Volume Control on panel—ample volume from built-in loud- 
speaker. 


Standard ZX-81—16K Rampack or printer can be plugged into ZON 
X-81 Sound Unit without affecting normal ZX-81 operation. 


* Huge range of possible sounds for games or: Music, Helicopters, 
Sci-Fi, Space Invaders, Explosions, Gun-shots, Drums, Planes, 
Lasers, Organs, Bells, Tunes, Chords, etc., or whatever you devise! 


8 full octaves. Uses 3-channel sound chip giving programme control 
of pitch, volume of tones and noise, all with envelope control. 


Easiiy added to existing games or programmes using a few simple 
“BASIC” lines or machine code. 


* No memory addresses used—l.0. mapped. 


FULL Instructions with many examples of how to obtain effects and the 
programmes, supplied. Fully Guaranteed. 


Payment may be made by Bank Cheque or International Money Order in 
U.S. $ or £ Sterling Payable to: 


P.O. Box 6 
Visa-Mastercard accepted 
ai a a Send account # 
“Phone pron 3182 | with name & address 


+ 


> 


> 


> 


%* 


10) Type GOTO 5 and ENTER. Type menu 
item #8 and your budget page will be on the 
screen. As each budget expense item appears, 
type in and ENTER your budgeted amount for 
that item. When the screen shows a report 
code 5 at the bottom, press “C” for the next 
page. 

11) Delete listing statements 3100, 3105, 
3120, and 3135. 

12) You must now load the computer with 
additional data in order to make your program 
work right. This is done with LET statements, 


2 REM +2 ¥*#***F DESIGNED BY 
ALAN PATTISON. OLYMPIA. WA 
S5 REM “MONEY MANAGER" f 
6&6 REM MA=NISC. ASSETS, X=CHECE. 
»yV=VUISA. S=SAUINGS .C=CASH,CD=C 
QF DEP.,.ST= STOCKS., MG= MORTGE 
LN LOAN 
$ “5 LET T = + mame 


uid TT be 
(iti 


AG 


haps 
me 
T 
pa 
eH 
Z 
~ 


Hant 
aN 


PUY e p 
E 


PRINT “BO YOQu WANT TO:” 
PRINT 
PRINT TAB 2: “23 CHECK INCOME 
STATEMENT? 
SS PRINT TAB “27 CHECK EXPENS 
= STATEMENT?" 
ið PRINT TRE SICHECK ASSETS 
AND LIABILIT IE: 
45 PRINT TAE ta) ENTER INCOME 
LEMS 27 
S@ PRINT TAE 1. “S53 ENTER EXPENS 
aS 8g os Te 
SS PRINT TAB 1, "“6)S5EFE& INCOME/E 
PENSE GRAPH?" 
SS PRINT TARE 1; "7)ISEE 2-YERR E 
XFEENSES GRAPH? 
SS PRINT TAB 1: “8? COMPARE EXPE 
NSES WITH BUDGET?" 
GO PRINT TRE 1: °3;3 SEE CASH FLO 


1 PRINT “103 TRANSFER FUNDS: F 
=PAY LOANS T* 
PRINT “11}3}5EE MONTHLY INCOF 
= EXPENSE?" 
63 PRINT “i23EXITtT PROGRAM?" 
64 PRIN 
eo “ENTER YOUR CHOICE, L 
70 INPUT QD 
75 CLS 
að IF O=1 THEN GOTCQ 200 
SS IF G=2 THEN GOTO 5ee@ 
SG IF OQ=3 THEN GOTO 8&@@ 
S IF O=4 THEN GOTO 3200 
188 IF O=5 THEN GOTO 5820 
185 IF O=6 THEN GOTO 4806 
i1@ IF G=7 THEN GOTO 2000 
115 IF OG=8 THEN GOTO 3ee8 
118 IF G=S3 THEN GOTO 66606 
i329 IF 0=1@ THEN GOTO 65800 
i120 IF G=11 THEN GOTO 7500 
ż21 IF O=i2f THEN GOTO 1000 
züt REM *INCOME STATEMENT Æ 
21i@ REM AFTER ENTERING CATEGORI 
ES, DELETE 235. 236,238., 239.241,2 
42. 235., 260, 285 
223 PRINT TAB 123° ag 
225 PRINT TAB 12: “E INCOME 
230 PRINT TARE ta: * KI 
#32 PRINT F 
z395 DIM L$(6&.15} 
236 DIM HiG} 
2385 DIM F (6? 
#39 LET M$="MONTH" 
22 


entered one by one (numbering not neces- 
sary). The titles may be changed to fit your 
own situation. Type in as follows: 
a) Load your Assets: 
LET X=(Checking account balance) 
LET V=(Visa or other cash card balance) 
LET S=(Savings account) 
LET C=(Cash on hand) 
LET CD=(Certificates of deposit) 
LET ST=(Stocks and bonds) 
LET PR=(Real and personal property) 
LET MA=(Other assets) 


Listing 1. 
24@ PRINT “ITEM: TAB 16: M$; TAB 
ao; “YEAR* 
242. Let Hee 
ee Veo he ee ee 
245 PRINT 5$ 
250. FOR B=2 TO 6 
255 INPUT L€t53 
250 INPUT Ht(B}3 
26S INPUT F (53 
z7 PRINT LS$(B)}; TAB i6;H(B);TAE 
=4,F iB?) 


z Fẹ 

228 PRINT “TOTAL; TAB 16; HT;TARE 
24; FT 

z291 PRINT TẸ 

“TYPE “"“ai'* FO MAKE € 


oe" TO RETURN TO S&S 


TART. ` 
394 ` INPUT 
295 CLS 

IF W=2 THEN GOTO 5 
299 REM +INCOME ENTRIES 

_31@ PRINT 


326 INPUT K$ 
33@ IF Kg="NO™ THEN GOTO 374 
342 FOR Z=2 TO 6 STEP 1 


372 PRINT “TYPE MONTH-S3 LETTER 
ie ge PORE 

373 Me 
374 as. 
375 PRINT TAB 6; “INCOME ENTRIES 


376 PRINT 


SẸ 
3850 PRINT “TO END ENTRIES TYPE 
ae “RETURN sa ue u 


390 PRINT "Ta 
395 PRINT TAS i16:;N6; TAB 25; “WER 


336 PRINT S 
400 PRINT me A a EE 


PS 
415 IF Pg§=" = Ae eal THEN GOTO 5 


6 
LiB} 
} THEN GOTO 452 


INT 
450 GOTO 480 
452 PRINT L$tSi; TARE i6;n(6) ; TARE 


eee st Ss 


= 
455 PRINT “$"°:;E 
ae RCCTF.: “i 


464 IF Ug="X" THEN LET te pe 

=3s += 
468 IF UgGa"U" THEN LET VsVe1E 
4708 IF wg="C“ THEN L C=C+E 


ET 
472 IF UgG="“CD“ THEN LET CD=CD +5 
474 IF tUg="“ST“ TREN LET ST=5fT +E 


“TS THIS A NEW MONTH? 


b) Load your Liabilities: 

LET MG=(Mortgage principal balance) 
LET L=(Other loan balance) 

13) Type GOTO 5 and ENTER. Your pro- 
gram is now Set up for you to use. If you are 
starting the program in the middle of the year, 
enter income and expense items month by 
month for all prior months. This is important 
if your graphs are to work correctly. If you do 
make entries for prior months, your balance 
sheet will no longer be correct. Therefore you 
should go back to instruction #12 and reload 
your Assets and Liabilities. 


475 IF Ug="“MA" THEN LET MASMATE 
476 LET HiB? =H (6) +E 
LET nT +E 


RT = 
480 LET F (653 =F (65) 4E 
482 LET FT=FT +E 


NT FS 
aur DATE"; TAB 16; H (6) 


FẸ 
456 INT “TOTAL INCOME; TRE 16 
HT TAB 24; FT 

438 PRINT S$ 

438 GOTO 4866 

SØG REM EXPENSE STATEMENT € 

S@S REM AFTER ENTERING EXPENSE 
54a SSE ESE’ DELETE 5219.522, 523, 

+ 


525., 528,527,528, 591. 532,593 
"EXPENSES 


219 LET D$="“MONTH" 
“ITEM"; TAG 16,08; FRE 


Al gars} 


i; TRE 16; MiNI; TRE 


FS 
Arey PRINT “TOTAL"; TAB 16; MT; TRE 


570 PRINT " ive PE "“"“i"" TO MAKE E 
i t van e TORETE IRN TO A START z 
37e INP 


UT U 
$75 IF ŲW<:>1 THEN GOTO 5 
578 REM ŽEXPENSE ENTRIES# 


‘PRINT 
591 PRINT “IS THIS A NEW MONTH? 
582 INPUT Y$ 


S83 IF YS="NO"' THEN GOTO 599 
en VWS="YES" THEN LET PPT=6 


SSS PRINT “TYPE MONTH-S LETTER 
ABBREVIATION 
S86 INPUT 


DS 
S9@ FOR D=1 TO 17 STEP 1 
MTF =8 


600 PRINT TRE &; “EXPENSE ENTRIE 


6@1 PRINT S& 

682 PRINT “TO END ENTRIES TYPE 
ay “RETURN ee ae ú ae 

683 PRINT T$ 
og PRINT TAG 15;D$: TAB 25; “WER 


607 PRINT SẸ 
688 PRINT “ITEM:"“ 


SYNC Magazine 


If you're shopping for a personal computer, for 
peripherals, for games—or practically anything that 


NEED HELP BUYING n 
A COMPUTER iae arcjust too many products on the market 
OR PERIPHERAL? ie Genive Computing 1983 Buyer’ Guide 


to Personal Computers, Peripherals and Electronic 
Games contains all the help you'll need to shop 
wisely. Its honest evaluations are written by 
experts—the experts of Creative Computing. 


In the Buyer’s Guide you'|l find: 
w How to select the computer for you 


= Evaluations of specific personal 
computers 


= Tips on buying peripherals of all kinds 
m Reviews of peripherals 
ii 
a 


Music synthesis equipment 


Comprehensive evaluation of joysticks, 
paddles and game port extenders 


Video game systems and software 
Roundup of electronic toys and games 


a 
= 
Æ Electronic and computerized learning aids 
E Video products for computer users 

x 


Selected microprocessor-based consumer 
electronics products. 


As you can see, the Buyer's Guide is an 
incredibly comprehensive directory to the latest 
in computer technology. Use the coupon below 
to order your copy today! 


ORDER YOUR 


oe COPY TODAY! 


Creative Computing 
Buyer’s Guide to Personal Computers 


P.O. Box 640, Holmes, PA 19043 
p Please send me the Creative Computing 1983 Buyer's 
Y P § ° Guide to Personal Computers, Peripherals and Electronic 


Games. | enclose $5.00 ($3.95* plus $1.05 postage and 
handling). Price outside U.S.A. $6.00. 


Mr./Mrs./Ms. 


(please print full name) 


City creative compating 
BUYER’S GUIDE TO 
PERSONAL COMPUTERS, 
PERIPHERALS AND 


ELECTRONIC GAMES 


Stile aA e SS 


Zip 


*NJ residents add 5% sales tax. 


Please make check payable to 
Creative Computing Buyer’s Guide. 


pete 
GETT 


i 

i 

i 

: 

i 

; 

] 

; 

| Address Apte- -> 
| 

i AE EET ies et SOA 
' 

| 

i 

: 

| 

| 


JUST 
4 $3.95 
o a 


Money Management 


628 INPUT 


, continued 


Cy 
615 IF Sete ce. THEN GOTO 5 


628 LET J=LEN 
630 DIM X$tiF.d3 


640 FOR N=i TO i7 
656 LET X$ (Ni =ISiny 


666 IF C¢= a edie 
678 NEXT 


THEN GOTO FOGO 


PRINT “NO SUCH CATEGORY --TY 


6Se . 
PE AGAIN.” 
635 GOTO 695 
TOO PRINT I¢{N} 
PRINT “ANT.: 


K 
716 PRINT “GSK 
715 PRINT oe 


720 PRINT 


STRE 16. Mtn} > TRE 


ROCT.: “i 


Q E 
722 IF O$=“X“ THEN LET X=X-K 
ved IF O$="S" THEN LET S=S-K 
725 IF &$=“U" i CET ESER 


727 IF og¢="Cc" 


EN LET 


730 LET M{N} =M IN) +K 


73S LET MT=MT+K 


F40 LET T iN? =T iN} +K 


F$ 
745 PRINT “TO DATE“; TAB 16: MIN} 
; TAB N) 


Fs 
748 PRINT “TOTAL EXPENSE": TAB i 


SiMT; TAB 24;TT 
49 $ 
750 GOTO 685 


Saa REM sASSETS/LIABILITIES:* 
810 REM THESE ARE INITIALLY ENT 
ERED WITH LET STATEMENTS. 


S26 PRINT TRG 4; 


Se? PRINT. TRE 4; 


ABILITIES 


328 PRINT TAG 4: 


330 PRINT 

S32 PRINT S& 
846 PRINT TAB 3; 
S45 PRINT TAB 3; 
20;U_ 

8508 PRINT TARE 3; 
TRE 20,5 

355 PRINT TAB 3; 
2@;C 

s50 Moats TAB 3; 
865 PRINT TAB 3i 
5 

O78 PRINT TAB 3S; 
TAB 280;:M 

aS an PRINT TAB 3i 


aS B PRINT TAB 


t 
“BASSETS AND LE 
e: ROGER IES COTTE ERT ERR BERS 


“CHECKING BAL." 
“MISA BAL. "“; TAB 
“SAVINGS BAL." 
“CRASH BAL." TAE 
“CERTS. OF DEF. 
“STOCKS, TAB 26 
“MISC. ASSETS". 
“PROPERTY “i TRE 


3“ ASSETS"; TAG 


28 RIVA 40400 157 NALOR 
@ PRINT S 


88 
agoni PRINT TAB 3; 
S90 * ORINT TAB 3; 


a; 
393 PRINT TAB 
TRS 2; MG+L 
and PRINT So 


“MORTGAGE; TAB 
“INS. LOAN": TRE 


3; “B LIABILITIES” 


PR: TAB 3; “E NET WORTH"; T 
"20 (X tU+S +C COST +MA+PR) — IMG + 


i Sk | 
900 PRINT “ENTER ““O““ TO RETUR 
TO ART." 


920 GOTO 5 


990 REM EXIT PROGRAM INCLUDIN 


SAVE 


1800 PRINT “YOU HAVE INDICATED 


OU WISH TO EXIT 
18285 PRINT 


THIS PROGRAM." 


1910 PRINT “IF YOU HAVE MADE ANS 


CHANGES“ 
1815 PRINT 


1020 PRINT  ‘°‘ ppm 
ie SER Te 
7625 PRINT e DO NGT FORGET TS FE 


14a PRINT 


2858 PRINT “TO SAVE THIS PROGRE 
AS CHANGED EREPSRE THE TAPE REL 


18682 STOP 

1878 SAVE “MONEY 
1080 GOTO S 

189398 STOP 


ORDER. BEGINRECORDING. AND TYPE 


MANAGER 


1530 REM *#2-YR EXPENSE GRAPH 
1593 REM AFTER RUNNING 1700., DEL 
STE 1700,1720. 1742 

2696 REM LAST YEARS MONTHLY EXPE 


NSES ARE ENTERED 


Witt LET STATE! 


ENTS-Riis TO R (25) (EVERY ALTERNS 


TE NUMBER) 
irga DIM Rife} 


1720 FOR I=i To 29 


2891 PRINT AT 8.9; 


S& 


28@2 PRINT “IT WILL TAKE A Cousi- 
E OF MINUTESTO PREPARE GRAPH... 7 


AKE A BREAK. 
2003 PRINT Ts 
2004 PAUSE 200 
2005 IF D¢="JAN" 


2210 IF D=“ “FES” 
2815 IF Dg="MAR™ 
S828 IF OF=“Arpr” 
2825 IF Os="“NAY 

2030 IF D$="UUN 

#2435 IF O$="4IUL" 
#3408 IF DgF="RUG" 
E45 IF O¢=“SEP" 
2858 IF Dg="GCcT" 
24 


THEN: LET 
THER CET 
THEN LET 
TEER HET 
THEN LET 
ATEN LET: 
THEN LET 
THEN LET 
THEN LET 
THEN. LET. 


OOOO O60) 0 
Hon nhnnnnon 


FU te foes fe > b> OOTP 1) 
G oy re a Gt 


zara LET. Q 


2855 IF OFf="NGU" THEN LET 
sago IF PEE aha THEN EE 


=MT 


2265 FAS 


2280 LET R íG} =& 


2500 CLS 
3108 FOR I= 

2520 PRINT 

Saro FOR U= 


25.70 G@ STEP >t 
AT ABS F-15.1<«5: Lee: 
i TG 24 


340 IF NOT Ritii THEN =@noToO 265 
2550 LET Y=R tuUu} +220 


2g60 IF Wc¢c-25 THEN PRIM 
#561 IF U=2 THEN GOTO 
3 THEN GOTO 


h 

fi 
a 
ny 
ke 
"Nl 
Q 


I ND fa ae 


2563 IF U=5 THEN GOTA ; 

2564 IF U=F THEN GOTG 2555 

2565 IF U=S9 THEN GOTO 2585 

2566 IF UB=11 THEN GOTO 2565 

2567 IF U=13 THEN GOTO 2555 

2568 IF U=15 THEN GOTO 2555 

2569 IF U=17 THEN SGO 2355 

2570 IF ti=iS THEN GoTo 2555 

2571 IF B=21 THEN GoTo 25585 

2572 IF U=25 THEN GoTo 2565 

2575 IF W:?-26 AND W<25 THEN PRE 
> mm ¿ 

2580 IF yY>24 THEN PRINT “BF; 

2382 NEXT Üü 

2585, IF VW? -26 AND Y:25 THEN PR: 

2588 IF Yo24 THEN ECRINT “REN: 

25390 NEXT U 

z500 PRINT 

2510 NENT I 

26209 PRINT AT (26,9, "610 F MAY 

JU ASGOAN G 

2630 PRINT AT 17.0; "52 3 FM A 
Jd AS: 6 > Oe 

2635 PRINT AT 19,7; “EXPENSE 19 
2538 PRINT AT 21.6: “iTYpE veo 


at 
i 
D 
i 
È 
n 
A 


2546 STOP 


255@ GOTO 5 


30300 CLS 


S335 REM BUDGET + 
328336 REM AFTER ENTERING BUDGET, 
DELETE 3100.3105. 3129.391935 


3310 PRINT 


TAB ee 


TS 
EXPENSES": TAB 16; “TOG 


DATE"; TAB 25: “BUDGET* 
3840 PRINT S$ 
2188 DIM P17) 
3195 LET BT=e 
2110 FOR N=1 TO 17 
32115 PRINT IG(Ni; TAB 16; T(N}; 
31230 INPUT PIN; 
3130 PRINT TAB 25; Pin; 
2135 LET BT=B8T +P (N) 
3348 NEXT N 
3150 PRINT F$ 
3170 PRINT “TOTALS“:TAB 16:TT:i TA 
3 25;58T 
3175 PRINT Ts 
3176 PRINT 
3130 PRINT “ENTER ““C'" TO RETUF 
N TO START." 
3185 STOF 
2138 GOTO 5 
3350 REM *xINCOME-EXPENSE GRAPH: 
3590 REM DELETE S369©,.3619@,.3620 A 
FTER RUNNING 3600 
2500 DIM Wtad2 
3510 FOR I=1 TO 29 
3520 PRINT I;“ t 
4800 CLS 
¿001 PRINT AT 86.0: 5$ 
4302 PRINT “IT WILL TAKE A MINUT 
= OR TWO TO PREPARE GRAPH......5& 
Oo HAVE A CUPOF COFFEE." 


45863 PRINT 
#BOd eee 


fon 

& 

Ui 

& 

t 

g) 
ASIST IS 
ICI RY FE te H H 4 


ds 
& 
M 
i) 
1 
D 
Kn 


4065 LET 


4500 CLS 
4510 FOR I= 
452@ PRINT 


TẸ 
200 
D=2 
D=4 
D=6 
="“APR“ THEN LET D=8 
=“MAY" THEN LET D210 
=“JUN“ THEN LET D=12 
=“.300i THEN LET DO=24 
=“RUG" THEN LET D=26 
ns toy P“ THEN LET D=25 
=“OCT THEN LET D=20 
=“NOU THEN LET D=22 
=“DEC THEN LET D=24a 
MT 
HT 


iS TO 8 STEP -1 
AT A6S I-15, I(5; Lea; 


4538 FOR U=i TO 34 
4549 IF NOT Wits} THEN GOTO 4686 


#558 LET Y 


=U (U3 +-I+286 


45600 IF Y<-2S THEN PRINT “ “i 
435651 IF U=12 THEN GOTO 45855 
4562 IF U=3 THEN GOTO 4565 
4563 IF U=5 THEN GOTO 45685 
43554 IF U=7 THEN GOTO 4565 
4565 IF U=3 THEN GOTO 45655 
4366 IF ŅY=11 THEN GOTO 45865 
45657 IF U=s=is THEN GOTO 4585 
45583 IF U=iS THEN GOTI 4565 
425593 IF U=17? THEN GOTO 4565 
4578S IF U=i9 THEN GOTO 4585 
457i IF U=21 THEN GOTO 4585 
$572 IF V=23 THEN GOTO 4565 
“W>-26 AND Y<¢25 THEN PRIN 


4575 IF 


: me . 
458@ IF vas THEN PRINT "H: 


4532 NEXT 


4585 IF Y>-26 AND Y:25 THEN PRIN 
Tv a7 ars 


4558 IF Y>24 THEN PRINT “wn: 
43530 NEXT U 


24608 
25186 


pari > 


IE 
ase. 
J A 
SB4G 


PRINT 
NEXT I 


JAF 16.2,“ TRLEITEISERIE 


BRINT AT 27,.2:;" UFMARM YU 
PRINT AT 29.5; “INCOME AND E 


XPENSE 1962" 
S@S@ PRINT AT 22,6; “CTYPE tgs" 


R 


RER- CASH PLOW STATEMENT è 
PR i@; 


PRINT TAB 16; M$: TAB 25; “VER 
PRINT Sẹ 
PRINT “INCOME: “; TRE 16;HT;T 


PRINT “EXPENSE: “; TAG 16; MT; 


PRINT “LOAN PRIN. PD.: “; TARE 


16; PPT; TRB 24; PPX 


6125 


6158 


PRI 


PRINT “NET: “i; TAB 16; HT -MT -P 


ST; TAB a4; INT f tet TT Bex) 150+. 
33 7100 


6166 
6173 
51588 


pein Te 
PRINT “ TYPE “"“C'" TO RETU 


RN TO START.” 


6130 
5200 
6500 
6518 


STOP 

GOTO 5 

CLS 

REM LOAN REPAYMENTS AND TF 
= 


6550 PRINT “WHICH CATEGORY DO YG 
WANT? ENTER ““G"" GR “Son 
5560 PRINT 

657@ PRINT “ 1} PRINCIPAL PAYMENT 


LORNS“ 
PRINT 


5580 PRINT “ 23 TRANSFERS BETWEEN 
ACCOUNTS“ 

6530 INPUT CR 

6600 IF CAEI THEN GOTO 7606 
S602 CLS 

6605 PRINT “WHICH LOAN ARE YOU P 
AYING ON? ENTER - CETS GR "a? 

6696 PRINT 

6506 PRINT TAB 5; “1} MORTGAGE" 


6609 PRINT 

tay PRINT TAB 5: “2)} INSURANCE UG 

S612 INPUT Z® 

6615 CLS 

66168 IF 29=2 THEN GOTO 6625 

6619 PRINT TS 

6628 PRINT “MORTGAGE: “ 

6621 PRINT S$ 

6622 GOTO 6658 

56625 PRINT T 

6626 PRINT “INSURANCE LOAN: “ 

6627 PRINT 

66390 PRI 

6631 PRINT Soe aAA INCLUDE INTE 
REST HERE - S D BE ENTEREG 
WITH CUR- RENT EXPENSES.” 

6635 PRINT 

6640 PRINT “PRINCIPAL PARYMENT = 
oa 

66596 INPUT PP 

6655 LET PPT=PPT +PP 

6656 LET PPX=PPX+PP 

6666 PRINT “SIPP 


63986 


SH TO TRA 


ts. sig h: ge 


PRINT “PRID FROM WHICH ACCO 


$ 
IF ZQ@=2 THEN LET L=L-PP 
IF ZO=i THEN LET MG-MG-PP 


sprees N° PRINT “NEW INS 


S$ 
PRINT “TYPE “Yin IF WOU WVE 


IF KK=2 THEN GOTO 5 
IF KK=3 THEN GOTO 6662 
IF KK=4 THEN GOTO 880 


Sg 
PRINT “AMT. YOU WISH TO TRE 


INPUT WE 
PRINT WE 


SB PRINT “FROM WHICH ACCOUNT? 


INPUT We 
PRINT WE 


PRINT Use WHICH ACCOUNT? “i 


US 
IF W="S“ THEN LET S=5-NE 
IF We="“MA“ THEN LET MA=MA-L 


SYNC Magazine 


7120 IF US="U" THEN LET V=sU-NE 
7130 IF We="X" THEN LET X=X-NE 
7i@@ IF WE="CO" THEN LET CD=CD -i 


E 

es IF N=“ST“ THEN LET STt=ST -U 
7160 IF We="C“ THEN LET C=C-NE 
Five IF Vs="S"“ THEN LET S=S+tve 
E IF VESUMA“ THEN LET MA=MA +H 


7190 IF aaa THEN LET V=U4vEe 
7200 IF V$="X" THEN LET X=X+4WE 
7210 IF Vg="CD“ THEN LET CD=CD +43 


VUge"ST" THEN LET ST=ST +H 


IF VUg="C“ THEN LET C=C+4v& 
7235 PRINT TS 


- PRINT 
7250 PRINT “TYPE ““2"" IF YOU WT 
SH TO MAKE ANOTHER TRANSFER. 
bieteat Sua” % time gC 8 | WISH TO RETURN T 


START. “"“S"" TOGO SEE REVISED AC 
COUNTS.“ 
7260 INPUT JE 
7265 CLS 


72708 IF JE=1 THEN GOTO 7806 
7275 IF JE=S THEN GOTO E00 
7290 GOTO 5S 


CLS 

7505 REM MONTH BY MONTH INCOME; 
EXPENSE DIFFERENCE. AND MEANS* 
7518 PRint 


MONTHLY INCOME AN) 


TS 
7550 PRI “MONTH TAG 7: “INCOME 
=i boce: tas “EXPENSE”; TAB 22; “DIFFE 


S 

7570 LET R=" ‘JANE EGMARAPRMAY JUN a 
ULRUGSEPOCTNOVUDEC"™ 

7571 LET HH=0 


7625 IF WiB)>® “THEN LET HH=nR+ 1 
7636 NEAT B 


7548 PRINT 


7SS@8_ PRINT TAG 8i IL: TRE 


NTER Sa TO INCLU 


TE 
7718 PRINT TAS .  EINCGME™ i. TRB i4 
Pas iz eit 55:3 DIFFERENCE" 


Si IL: TARAB ISi EE:TKH 


7735 PRINT F$ à 
7740 LET PP=INT (NGX-MG) is 
7750 PRINT “PRIN.“; TAB @; “PMTS. 


r 
7770 PRINT “YEAR: THE i II:TRG 2 
S; EE+PP ; TRG 23; LI-EE-PP 
@ PRINT 
7790 PRINT S 
7791 LET B8-6 
7792 FOR B=1 TO 24 STEP 2 
7793S LET RAR 1B; 
7794 LET BB=-GE+AÑ 


7795 NEXT & 
FSeos PRINT “HEGN MONTHEL NEPE- 
tiII? HHI HE aT <3 SP 


nes g§° INT 
3310 PRINT “NEAN MONTHLY EXPENS 
t IEE rH BELG EES t. 5j: iG 


ae gE“ INT 

£2 

7316 PRINT “MEAN EXPENSE LAST r 
2: $“; ENT €({BG27123 £102 42+.53 -is 


“{£# SEXCLUDING MORTGAHYG 


(94 


os 
7330 PRINT “ ENTER at, re 
N TO START.” 


Ed. — For the convenience of our readers 
the author will supply the program on 
cassette for $8 including postage. Readers 
outside the U.S. should include in the 
payment enough to cover the additional 
cost of postage for about 2 ounces. 


Line Notes: . 


7: § 

cis SS 

iS: Inverse: 

70: Letter O 

210: Once you have entered 
your income categories, delete 
statements indicated in REM. 


20% 5 6 


MONEY MANAGER 


Cont O g 


2S0: -Z 

255: Your income categories 

464: IF, LET statements 
credit the income to the proper 
account. 

486: Frints a running total 
of both monthly and year-to-date 
income. 

30S: Once you have entered 
your expense categories, delete 
statements indicated in REM. 

aes A 

glas: a & 

alas- zZ 

Z722: IF, LET statements debit 
the appropriate account. 

810: Initialize each asset 
and liability balance with LET 
statements. 

Ba/s oS B 

828: 7 

865: Change titles of assets 
and liabilities to suit your own 
needs. 


875: Inverse > on M 

B7Ss Inverse =: Dn 4 

896: Inverse spaces; = an M 
1020: 6 

19025: 3, 8 

1930: Z 


1695: These 3 statements set 


up your graph but should be 
deleted after running. R11) 
would be Jan. expenses last 
years RS) Feb., etc. These will 
only appear on the graph when 
you enter each month this year, 
but they will be in memory 
waiting. 
Zale: © 
2280: Inverse space 
2388: A 
2620: 81 represents last year 
(change to suit your needs); 
space between each letter 
representing a month; 82 
represents this year. 
32006: Delete statements in 
REM after entering all your 
budget items. 


3010: ó 

SOL Da 2.. 8 

S020- Z 

3390: Delete statements 
indicated in REM after running 
S600, 

4063: 

4080: 

4570s 

4375: 

4580: 

43855 

4388: 

BOBO: 
letter. 

6010: 6 

6020: J, 8 

6608: Change loan titles to 
suit your own needs. 

7520: A (2), A (2) 


Letter @ 
Letter oO 


IT ka 100 lo ka 


Space between each 


January/February 1983 


TO RETUE 


Sinclair Software SourceBook 
list 
YOUR SOFTWARE 
now for the February catalog 
SELL IT—SHARE IT 
You made it to fit your specific 
needs and it will meet the needs of 
thousands of other Sinclair users 
-who will 
ORDER FROM YOU AT YOUR 
PRICE 


software category 
[_] Business Applications 
[_] Educational 
[|] Games 
[C] Industrial 
[ ] Home 


Special Hardware if needed 


designed for 


[ ] ZX80 

C] ZX 81/Timex Sinclair 1000 
minimum of 

cya ETISK 

[]2k []48k 

[]16k [ ] 64k 


Brief description (200 characters 
max.) 


ay 8, 0, 6 >a Pee | yee. 6) E A E EN N T E E TE E E W 
2. er a wile a He h ole) T a ol esa see a ie Ae bole. Se A a N A 
ao dae) terse) are) 8-0 Ww a. vee! 4 a De - 6 ere se im) rb) a Sie, [eH wpl-0, se: le 
oe” 6s 8 O re” w 6. @ Orem te Ol a 6 “se cae (Oc a eee, Gene. Jel 6? a 
EA E a eae eo, 6-8 hee of eo) Ver se ie: ce) sel peo wie pe'lval ©, ee T E cm aw 
eo Sb eo: — 6" 0) le; eo ve eye J 6 et) ee 6) at Mal Set Sanne fe “aie, wee S N 
Bet BS Pye he Le apa ype teehee 6 a a ce er Barer jae ee E je ele 
eek 6" E Orea Jeo 8 68 Sp wl oe ome te cele ee ef .ee 8 Ss)... Semele, ee 


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AARDVARK — THE ADVENTURE PLACE 
ADVENTURES FOR OSI, TRS-80, TRS-80 COLOR, SINCLAIR, PET, VIC-20 


ADVENTURES — Adventures are a unique 
form of computer game. They let you spend 
30 to 70 hours exploring and conquering a 
world you have never seen before. There is 
little or no luck in Adventuring. The rewards 
are for creative thinking, courage, and wise 
gambling — not fast reflexes. 

In Adventuring, the computer speaks and 
listens to plain English. No prior knowledge 
of computers, special controls, or games is re- 
quired so everyone enjoys them—even people 
who do not like computers. 

Except for Quest, itself unique among Ad- 
venture games, Adventures are non-graphic. 
Adventures are more like a novel than a comic 
book or arcade game. It is like reading a par- 
ticular exciting book where you are the main 
character. 

All of the Adventures in this ad are in Basic. 
They are full featured, fully plotted adventures 
that will take a minimum of thirty hours (in 
several sittings) to play. 

Adventuring requires 16k on Sinclair, TRS- 
80, and TRS-80 Color. They require 8k on OSI 
oven on VIC-20. Sinclair requires extended 


TREK ADVENTURE by Bob Retelle — This 
one takes place aboard a familiar starship and 
is a must for trekkies. The problem is a famil- 
iar one — The ship is in a “decaying orbit” 
(the Captain never could learn to park!) and 
the engines are out (You would think that in 
all those years, they would have learned to 
build some that didn’t die once a week). Your 
options are to start the engine, save the ship, 
get off the ship, or die. Good Luck. 

Authors note to players — | wrote this one 
with a concordance in hand. It is very accurate 
— and a lot of fun. It was nice to wander 
around the ship instead of watching it on T.V. 


CIRCLE WORLD by Bob Anderson — The 
Alien culture has built a huge world in the 
shape of a ring circling their sun. They left 
behind some strange creatures and a lot of ad- 
vanced technology. Unfortunately, the world 
is headed for destruction and it is your job to 
save it before it plunges into the sun! 

Editors note to players — In keeping with 
the large scale of Circle World, the author 
wrote a very large adventure. It has a lot of 
rooms and a lot of objects in them. It is a very 
convoluted, very complex adventure. One of 
our largest. Not available on OSI. 


HAUNTED HOUSE by Bob Anderson — This 
one is for the kids. The house has ghosts, gob- 
lins, vampires and treasures — and problems 
designed for the 8 to 13 year old. This is a 
real adventure and does require some thinking 
and problem solving — but only for kids. 

Authors note to players— This one was fun 
to write. The vocabulary and characters were 
designed for younger players and lots of things 
happen when they give the computer com- 
mands. This one teaches logical thought, map- 
Ping skills, and creativity while keeping their 
interest. 


DERELICT by Rodger Olsen and Bob Ander- 
son — For Wealth and Glory, you have to ran- 
sack a thousand year old space ship. You'll 
have to learn to speak their language and 
operate the machinery they left behind. The 
hardest problem of all is to live through it. 

Authors note to players — This adventure 
is the new winner in the “Toughest Adventure 
at Aardvark Sweepstakes”. Our most difficult 
problem in writing the adventure was to keep 
it logical and realistic. There are no irrational 
traps and sudden senseless deaths in Derelict. 
This ship was designed to be perfectly safe for 
its’ builders. It just happens to be deadly to 
alien invaders like you. 


W7 


NUCLEAR SUB by Bob Retelle — You start 
at the bottom of the ocean in a wrecked Nu- 
clear Sub. There is literally no way to go but 
up. Save the ship, raise her, or get out of her 
before she blows or start WWIII. 

Editors note to players— This was actually 
plotted by Rodger Olsen, Bob Retelle, and 
someone you don't know — Three of the nas- 
tiest minds in adventure writing. It is devious, 
wicked, and kills you often. The TRS-80 Color 
version has nice sound and special effects. 


EARTHQUAKE by Bob Anderson and Rodger 
Olsen — A second kids adventure. You are 
trapped in a shopping center during an earth- 
quake. There is a way out, but you need help. 
To save yourself, you have to be a hero and 
save others first. 

Authors note to players — This one feels 
good. Not only is it designed for the younger 
set (see note on Haunted House), but it also 
plays nicely. Instead of killing, you have to 
save lives to win this one. The player must 
help others first if he/she is to survive — | like 
that. 


Please specify system on all orders 


PYRAMID by Rodger Olsen — This is one of 
our toughest Adventures. Average time 
through the Pyramid is 50 to 70 hours. The 
old boys who built this Pyramid did not mean 
for it to be ransacked by people like you. 
Authors note to players — This is a very 
entertaining and very tough adventure. | left 
clues everywhere but came up with some in- 
genous problems. This one has captivated 
people so much that | get calls daily from as 
far away as New Zealand and France from 
bleary eyed people who are stuck in the 
Pyramid and desperate for more clues. 


QUEST by Bob Retelle and Rodger Olsen — 
THIS AS DIFFERENT FROM: ALL THE 
OTHER GAMES OF ADVENTURE!!!! It is 
played on a computer generated map of 
Alesia. You lead a small band of adventurers 
on a Mission to conquer the Citadel! of Moor- 
lock. You have to build an army and then arm 
and feed them by combat, bargaining, explora- 
tion of ruins and temples, and outright ban- 
ditry. The game takes 2 to 5 hours to play 
and is different each time. The TRS-80 Color 
version has nice visual effects and sound. Not 
available on OSI. This is the most popular 
game we have ever published. 


MARS by Rodger Olsen — Your ship crashed 
on the Red Planet and you have to get home. 
You will have to explore a Martian city, repair 
your ship and deal with possibly hostile aliens 
to get home again. 

Authors note to players — This is highly 
recommended as a first adventure. It is in no 
way simple—playing time normally runs from 
30 to 50 hours — but it is constructed ina 
more “open” manner to let you try out ad- 
venturing and get used to the game before 
you hit the really tough problems. 


ADVENTURE WRITING/DEATHSHIP by 
Rodger Olsen — This is a data sheet showing 
how we do it. It is about 14 pages of detailed 
instructions how to write your own adven- 
tures. It contains the entire text of Deathship. 
Data sheet - $3.95. NOTE: Owners of OSI, 
TRS-80, TRS-80 Color, and Vic 20 computers 
can also get Deathship on tape for an addi- 
tional $5.00. 


PRICE AND AVAILABILITY: 

All adventures are $14.95 on tape except 
Earthquake and Haunted House which are 
$9.95. Disk versions are available on OSI and 
TRS-80 Color for $2.00 additional. 


ALSO FROM AARDVARK — This is only a partial list of what we carry. We have a lot of other games (particularly for the 
TRS-80 Color and OSI), business programs, blank tapes and disks and hardware. Send $1.00 for our complete catalog. 


A 


= 


AARDVARK - 80 


2352 S. Commerce, Walled Lake, MI 48088 


(313) 669-3110 


Phone Orders Accepted 8:00 a.m. to 4:00 p.m. EST. Mon.-Fri. 


TRS-80 COLOR 


SINCLAIR 


OSI VIC-20 


8K ROM 
1K RAM 


Checkbook Management 


George J. Repicky 


A computer with its TV display, makes the 
task of updating and balancing a checkbook 
simpler than using a four-function calculator. 
The display enables the user to double-check 
entries and so helps eliminate mistakes. In 
addition, if mistakes are made, they are easily 
corrected. Below are two programs which I 
developed for these purposes. Each requires 
the 8K ROM, and each fits into IK RAM. 


Program 1 
If you are like most people, you make a 
number of transactions—write checks, make 
deposits, etc.—with your checkbook before 
you update the balance. The first of the two 
programs is designed to update your 
checkbook balance. To use the program, enter 
it into the computér, then RUN. 
The program first asks you to 
INPUT BALANCE 
At this point you enter your last computed 
balance. 
Then the program asks you to 
INPUT CHECK CHARGE 
In response, you enter the per check charge of 
your account. (If your checking account has 
no check charge, you can delete lines 220 and 
230, and the “-C” of line 380, from the pro- 
gram.) 
The program then clears the screen, and 
displays: 
INPUT CODE, THEN INPUT AMT. 
ITEM DEBIT CREDIT BALANCE 
At this point you enter each transaction in 
your checkbook in two steps. First, for each 
transaction you enter a code: 0 if the transac- 
tion was a debit (a monthly service charge, for 
example); 1 if the transaction was a credit (a 
deposit, perhaps); or the check number if the 
transaction was a check. Second, you enter 
‘the amount of the transaction. After each 
complete entry the computer displays the na- 
ture of the transaction in the first column, 
49 Roosevelt 


George J. Repicky, Ave., 


Schenectady, NY 12304. 


January/February 1983 


A, | 


yal 
Π


using DEB if the transaction was a debit, 
CRED if the transaction was a credit, or the 
check number if the transaction was a check; 
the amount of the transaction in the second (if 
the transaction was a debit or check) or third 
(if the transaction was a credit) column; and 
the resulting balance in the fourth column. 
For an example of how this works, suppose 
that your most recent balance was $110.10 and 
that your account charges you $0.25 per 
check. Upon entering these figures, the dis- 
play would show 
INPUT CODE, THEN INPUT AMT. 
ITEM DEBIT CREDIT BALANCE 
110.1 


Now suppose your next four transactions were 


check 215 for $50.; a $3.00 monthly service 
charge; a $240 deposit; and check 216 for 
$245.20. To enter these you would enter 215, 
then 50; 0 (for a debit), then 3; 1 (for a credit), 


then 240; and 216, then $245.20. The display 


would now show: 


INPUT CODE, THEN INPUT AMT. 
ITEM DEBIT CREDIT BALANCE 


110.1 
215 50 59.85 
DEB 3 56.85 
CRED 240 296.85 
216 245.20 51.4 


This display scrolls up with each entry, so 
you may continue until you have entered all 
transactions. The screen can hold eleven 
transactions at one time, so be sure you check 
your work from time to time. If you should 
detect an error, it can be offset using the 0 or 1 
code, and then the amount, to adjust the bal- 
ance appropriately. 


Program 2 
The second program is used to check your 
checkbook balance against your bank state- 
ment. When you run the program, it first asks 
you to 
INPUT CHECK CHARGE 
In response, you enter your account per-check 


charge. If your account does not have a check 
charge, you can delete lines 80, 90, and 100, 
and the ‘“‘-A” of line 190. Alternatively, if you 
will use the program for accounts with the 
same check charge, you can make line 80: 

80A = (check charge) and delete lines 90 
and 100. 

The program then asks you to 

INPUT BANK BALANCE 
In response, you enter your balance as per 
your bank statement. 

The program then asks you to 

INPUT OUTSTANDING CHECKS 

IF FINISHED, INPUT 0 
You now enter, one at a time, the amount of 


-each check which was not returned with the 


statement. As you enter the amount of each 
check, it is displayed on the screen. When you 
have entered all such checks, enter 0. 

This sends the program on to the next step 
which asks you to 

INPUT UNRETURNED DEPOSITS 

IF FINISHED INPUT 0 
Now you enter, one at a time, the amount of 
each deposit which you made since the state- 
ment was compiled by the bank, that is, the 
amount of each deposit which does not appear 
on the statement. As you enter the amount of 
each such deposit, its value will appear on the 
screen. When you are finished, enter 0. The 
computer will now compute your correct 
checkbook balance (assuming the bank has 
not made a mistake!) and display 
CHECKBOOK BALANCE SHOULD BE: 
(balance) 


Memory Saving 

In entering the program, you should use 
keywords and tokens wherever possible in the 
PRINT statements. This saves considerable 
memory and is necessary if the program is to 
run in IK RAM. 

To use this procedure (from Richard 
McDaniel, SYNC 1:5) enter the line number, 
then enter the last keyword in the statement. 
Then back up the cursor, using the left arrow 


27 


(shift 5) until it is before the keyword. Now 
enter the next-to-last keyword. Repeat this 
procedure until all keywords are entered. You 
can enter intermediate text as you work, or 
after all keywords are entered. 


An example may help here. Consider line 
260 from the first program: 
260 PRINT “INPUT CODE, THEN INPUT 
AMT.” 

To enter this line, first type: 
260 INPUT AMT.” 
using the keyword INPUT (on the “I” key). 


Program 1. Checkbook Update. 


INPUT BALANCE” 
R INFUF CHECK CHARGE” 


INPUT CODE , THEN I 


a GOsuUB zoga 
“ITEM” > TAR Si” “DEES F 7? i 
TAB 13, EREDE > TAB 21; “BALANCE 
2@ GQSUB 2eee 
235 PRINT TRB 21;8 
eee 


INPUT Z 
350 IF Y=1 THEN, COTO i1@8@ 
350 LET B=B-Z 
370 IF Y2t THEN PRINT Y; 
380 IF Y=@ THEN PRINT “DEB"; 
390 IF Y>1 THEN LET B=8-C 
4@0@ PRINT TAS 5; Z; TAB 21; BR 
41¢e og he 318 


B=B+z 
1010 PRINT “CRED; 


ig2e@ GOTO 312 
2820 SCROLL 
2010 PRINT 
2220 SCROLL 
22308 RETURN 


FRB 12; Z FRB = 


Line notes: 


210: Enters the previous checkbook bal- 
ance. 

230: Enters the per check charge. 

280: Sets the headings of the transaction 
listing. 


300: Prints previous balance in col. 4. 

320: Enters code -0, 1, or check no. 

340: Enters amount of transaction. 

350: Branch if transaction was a credit. 

360: Decreases balance for debits. 

370: Prints check no. if transaction was a 
check. 

380: Prints DEB if transaction was a non- 
check debit. 

390: Decreases balance by per check 
charge if transaction was check. 

400: Prints amt. of trans. and resulting bal- 
ance. 

410: Returns for next transaction. 

1000: Branch from 350; increases bal. for 
credit. 

1010: Prints amt. of trans. and resulting 
balance. 

1020: Returns for next transaction. 

2000: Scroll and space subroutine; used 
after each line of display is printed. 
2030 RETURN 


Ca 


CYBORCGWARS 


NOT ANOTHER TOY 


BUT A COMPLEX SIMULATION OF FOUR MILITARY- INDUSTRIAL 
ECONOMIES LOCKED IN A DEADLY STRUGGLE FOR SURVIVAL. 
ONE TO FOUR PLAYERS COMPETE WITH EACH OTHER AND/OR 


THE COMPUTER. 


BALANCE OF POWER DEPENDS UPON 


SKILL IN DEVELOPING RESOURCES, USE OF ESPIONAGE, 
EXPLOITATION OF ALLIANCES, AND UTILIZATION OF MILITARY 


POTENTIAL. 


ED sa 


REQUIRES ZX81 WITH 8K ROM AND 16K RAM. 


eae 
f 


ORDER FORM FOR CYBORG 


Send $14 (plus $1 for shipping) to: 


STRATAGEM CYBERNETICS, INC., 


286 Corbin Place, 2E, Brooklyn, New York 11235. | 


i _ Se ees Sa hee dy gee ee 


is e A mm 
aoe ù (| nig batik aie 


: MMW hes wos 
en Se 


28 


Then back up using the left arrow (shift 5) 
until the cursor is before the word INPUT. 
Now enter THEN, using the token (shift 3). 
The display will read: 

260 THEN INPUT AMT.” 

Back up again until the cursor is before 
THEN, and enter CODE, using the token. To 
do this you must first obtain the function cur- 
sor (shift NEWLINE or shift ENTER), then 
enter the token CODE, (on the “I” key). The 
display will now read: 

260 CODE THEN INPUT AMT.” 

The cursor is now after the word CODE, so 
now is a good time to enter the comma. Next, 
back up again until the cursor is before the 
word CODE, and enter INPUT, again using 
the keyword (on the I key). The display now 
reads: 


- 260 INPUT CODE, THEN INPUT AMT.” 


Finally, back up again until the cursor is 
before the word INPUT, and enter PRINT, 
using the keyword (on the “P” key). At this 


~ time also enter the leading quotation mark. 


The display will now show the complete line, 
ready to enter: 

260 PRINT “INPUT CODE, THEN INPUT 
AMT.” 

The whole thing sounds a bit complicated 
when you read it, but it is really quite simple 
once you get the hang of it. The memory sav- 
ing is substantial; 17 bytes for this one state- 
ment alone. a” 


Program 2. 
Checkbook Statement Comparison. 


70 SOSUB 2009 
5 = INPUT CHECK CHARGE” 


: 2000 i 
110 PRINT ” INPUT BANK BALANCE” 


R 
1230 GOSUB 2000 
" INPUT OUTSTANDING C 


5” 
150 GOSUB 200g 
ise cuaus sees 
17 
18@ IF C=@ THEN GOTQ 230 
190 LET &=8-C-A 


200 PRINT 


Cc 
210 GOSUB 2008 
220 GOTO 170 
230 GOSUB 2000 
24@ PRINT “ INPUT UNRETURNED DE 
POS 


ITS“ 
250 GOSUB 2000 
260 GOSUB 4008 


NPUT D 
2809 IF D=0 THEN GOTO 340 
B=B+D 


330 GOSUEB 2008 
PRINT “BALANCE SHOULD BE: “ 


Line notes: 


90: Inputs per check charge 

120: Inputs bank balance as per statement. 

170-230: Form a loop which inputs out- 
standing checks and adjusts the bank state- 
ment balance for them and associated per 
check charges. 

240-330: Adjust the bank statement bal- 
ance for any deposits made after the statement 
was prepared. 

340: Prints checkbook balance. 

2000: Subroutine used to scroll and space 
printout. 

4000: Subroutine to print statement. 


SYNC Magazine 


COBRA RS232C 
INTERFACE. 


At last, a high quality RS232C interface for the ZX81 
(TIMEX 1000) to connect you to any RS232C printer. 
Look at these features: 

Variable baud rate by software control. Upper and lower 
case printout. Up to 120 characters per line with soft- 
ware control. Handshake facility. Comprehensive man- 


COBRA CENTRONICS INTERFACE 


The same high quality as the RS232C except for the 
output being via a 24 way socket. Both interfaces have 
the same features. AT AN INTRODUCTORY PRICE 
OF ONLY $50.00 + $6.00 shipping. We also make 
every type of lead and plugs for the above interfaces, 

typical prices. 
25 way “D” connector with leads for above 232 $15.00 
4 way DIN plug and leads for the above 232 $15.00 


AVAILABLE JANUARY. 


Another first from COBRA. A truly intelligent RS232C 
interface. With this interface 2 ZX(TIMEX) computers 
can communicate with each other along any usable 
medium ie telephone, radio etc. Such information as 
listings, data strings and programs can be passed be- 
tween any number of computers very simply. The price 
is also unbelievable. For more details tick box below. 


Please rush me your (tick required) 


RS232C interface atonly .............-..- $50.00 L] 
Centronics interface atonly ..............- $50.00 L] 
Power supply buffer atonly ............... $22.00 L] 
Leads for the interface ................... $15.00 L] 
The free brochure from COBRA” ] 
More details of your 232 MODEM* LJ 


gO PL aLak 


Don't forget to add shipping to your order 
*Please send a stamped, self-addressed envelope for 
brochure. 


ual with every unit. Fits on the back like a RAM pack. 
Uses the ZX(TIMEX) power supply. Output via 2 small 


jack sockets. 


AT AN INTRODUCTORY PRICE OF ONLY $50.00 + 
$6.00 shipping. 


COBRA POWER SUPPLY BUFFER. 


Ever had hours of programming work lost in a moment 
owing to fluctuations in power or accidental switching of 
the wrong mains plug? 

The Cobra power supply buffer prevents such occur- 
rences affecting you. It is fitted between the Sinclair 
(Timex) power supply and the computer. During loss of 
power to the computer the buffer will continue to power 
the computer with a 9 volts supply for up to 30 minutes or 
more. It also has mains filtering circuitry to prevent 
spikes getting through to the computer. The unit will 
recharge itself during normal power on conditions. 
When a mains loss situation occurs a red LED will warn 
the user of loss of electricity supply. 

THE PRICE IS ONLY $22.00 + $7.00 shipping. 


Cobra Technology Limited, 378 Caledonian Road, Islington, London N1 1DY U.K. 


8K ROM 
16K RAM (1K RAM) 


A Loan Amortization Program 


Most manufacturers of large computers 
(mainframes and minicomputers) offer a set 
of “utility” programs either as a freebie with 
purchase of their computer, or as a low cost 
option. One program that inevitably shows up 
in those packages is a loan amortization pro- 
gram for calculating monthly payments and an 
amortization schedule on consumer loans or 
home mortgages. The usefulness of such in- 
formation is obvious. The payment tells the 
user how much of a monthly commitment he 
is making, and the amortization schedule how 
much of the payment is being applied to inter- 
est and how much to reduce the balance on the 
loan. 

Most loan amortization programs ask the 
user to specify three out of the following four 
items of information: the amount of the loan 
(the principle), the annual interest rate, the 
duration of the loan, and the amount of each 
payment. The program then calculates the 
missing variable and prints out the amortiza- 
tion schedule. Usually that is printed out in a 
columnar format with the payment number in 
one column and the following items in the 
other columns: the payment amount, the 
amount of the payment that went for interest, 
the amount that went towards repayment of 
the principle, and the remaining balance on 
the principle. 

Since I have a ZX80 (8K ROM) with only 
1K of user memory, I knew that I would not be 
able to deal with a lot of options, nor would I 
be able to do an entire amortization schedule. 
I decided that the operator would supply the 
loan amount, the interest rate, and the number 
of monthly payments. The program would 
calculate only the payment necessary to amor- 
tize the loan. If I had room left over after the 
basic program was coded, I would see what 
could be done about an amortization sched- 
ule. 

I first needed to find a formula for calculat- 
ing the equal loan payments needed to amor- 
tize a loan. Such a formula can be found in 


Gerald F. Hoag, 5112 16th Ave. So., Minneapolis, 
MN 55417. 


30 


Gerald F. Hoag 


virtually any consumer or practical mathemat- 
ics textbook at your local library. That for- 
mula is seen cn Figure 1. 


rate indicates how much interest applies to 
each monthly payment. 
Calculating the monthly payment, how- 


Figure 1. Loan Repayment Formula. 


periodic int. rate 


payment = loan amount X 
l- 


Before I started programming, I verified 
the formula by calculating a payment using a 
calculator and comparing the result with the 
payment amount listed in a loan payment 
book. 

With a formula in hand, it was easy to come 
up with the statements needed to ask for input 
from the operator and to calculate the periodic 
interest rate. Those steps are handled in lines 
10 through 70 of the program (shown in Figure 
2). As shown, the information input by the 
operator is printed out as soon as it is entered 
to form a record of the loan parameters and as 
a convenience to the operator. 

The periodic interest rate is found by divid- 
ing the annual interest rate by the number of 
payment periods in a year (the program as- 
sumes 12 payments per year). That interest 


— Figure 2. Loan Amortization Program (1K). __ 
18 PRINT “AMOUNT OF LOAN?" 
INPUT AMT 
ANT 
“ANNUAL INTEREST RATE 
4@ INPUT RAT 
RAT 
“LOAN DURATION 
6@ INPUT MO 
PRINT MO 
7@ LET INT=(RATi9@}3 712 
6@ LET DIVISOR=12+INT 


9@ LET DIVISOR=DIVISORe2MNO 
188 LET DIVISOR=i-(ti-sbDIVISOR) 


{MONTH 


118 LET P=AMT # (INT sDIVISOR) 

120 PRINT “PAYNMENT=";P 

138 PRINT 

140 PRINT “NO. INT PAID REDUCTEI 
ON BALANCE” 

145 LET = 


I=1 
158 LET INTPAID=AMT INT 
150 LET RED=P-INTPAID 
170 LET AMT =AMT -RED 
198 Opa zt “|; ENTPAID; Y“ 


a 
> 


as : RE 


(1 + periodic int. rate 


1 
) periods 


ever, was a trickier problem. When I first 
wrote the program, I tried entering the pay- 
ment calculation in one long program state- 
ment in algebraic format: 


LET PAYMENT =P * I/(1-(1/(1+1)**MO)) 


Besides the obvious difficulty in trying to get 
a valid statement with so many parentheses, I. 
also was getting the wrong answers because of 
the priority in which the ZX80/81 handles cal- 
culations (first exponentiation, then multipli- 
cation and division, and finally addition and 
subtraction). This produces wrong answers 
even though the formula is algebraically cor- 
rect. 

I decided to simplify the calculations, and 
also to get them in the proper sequence for 
calculation by first calculating the divisor of 
the formula as shown in the series of steps in 
lines 80, 90, and 100. Then, after I had the 
divisor, I could use a more simplified formula 
to calculate the monthly payment, as shown in 
line 110. 

Lines 120, 130, and 140 print out the calcu- 
lated monthly payment and then the headings 
for an amortization schedule. With a little ex- 
perimentation, I discovered that I would have 
enough memory left over to show the amorti- 
zation of one payment. Line 145, therefore, 
sets the payment number equal to 1. That is 
followed by calculation of the interest paid in 
the period, the reduction to the principle, and 
the balance remaining on the principle. For 
those with more memory, line 145 would be 
the appropriate place to start a FOR/NEXT 


SYNC Magazine 


loop to calculate a complete schedule. Just let 
the loop count equal the number of monthly 
payments (“MO”) and execute lines 150, 160, 


Figure 3. Sample Run (1K). 


AMOUNT OF LOAN? 
ANNUAL INTEREST RATE? 


LOAN DURATION (MONTHS) ? 


a 
PAYMENT =1133.36112 


NO. INT PAID REDUCTION BALANCE 
2 53.333999 690.927791 3939.9722 


IMPROVED HEAT SINK for ZX81 & 
TS1000 eliminates system crashes 
caused by veneer $7.95 

ASE for 


check/money order or 
complete details to: 
BASCO, 289 Baxter La, Milford 
CT 06460 


ATTO-SOFT 


PRESENTS 


ZX-MAN 


ZX-MAN. Turn your ZX8!I or TIMEX 
SINCLAIR 1000 into an arcade type game 
computer with ZX-MAN. 100% machine 
code makes this fast acting program as 
_ much fun as being at the arcades. With the 
joystick option you can have the real feel 
of game playing never before available for 
your ZX8İ or TIMEX SINCLAIR 1000. 
16K required.................. $14.95 


JOYSTICK. With ATTO-SOFT’s JOY- 
STICK your ZX8I or TIMEX 1000 can be 
turned into an arcade type computer allow- 
ing fast control over ZX-MAWN and other 
type software. Requiring only six simple 
solder connections inside your computer. 
Also included is software to develop your 
OWA DFORTAMS 0.5 siio 35's oes ewes $14.95 


(Please add $1.50 Postage and Handling. COD's add $2.00.) 
Send check or money order to: 


ATTO-SOFT 
832 E. Third Street, 
Galesburg, Illinois 61401 
(309) 343-4114 
AMERICAN EXPRESS ACCEPTED 


January/February 1983 


170, and 190 on each pass through the loop. 
Specifically, the NEXT statement in the loop 
would go on a line after line 190. 


Figure 4. Sample Run (over 1K). 


3939.97 


4 
2 
2 
4 
5 
& 
7 
B 
g 
4 
ee 
a 


Beet. 42 


Need a good game to play or pro- 
gram? Circle Chess board with in- 
structions $5.00. Send your record- 
ed Circle Chess games and pro- 
re for publication in Circle 

hess Journal, Box 63, Des 
Plaines, IL 60017. 


THE VIDEO 
REVERSER 


AT LAST REVERSE VIDEO FOR 
THE ZX81 AND TIMEX 1000 


White letters on a black 

back ground for connec- 

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send check or money order 
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ELECTRONICS 
1120 Bailey Hill Rd. #10 
Eugene Oregon 97402 


phone (503) 485-6274 


Figure 5. 
____ Additions to Figure 2 for over 1K RAM. ___ 


3S SCROLL 
14S FOR I=1 TO 48 
OLL 


75) 7100. TAB 23; INT TAMNT#2@@4+.5) 7 


að 
200 NEXF I 


Figure 3 shows a sample run of the program 
with the operator entering the amount of the 
loan, the annual interest rate, and the loan 
duration. The program echoes each of those 
entries by printing them back out. Following 
entry of the loan duration, the program calcu- 
lates and prints out the amount of the monthly 
payment and then the one month amortiza- 
tion. As you can see, a good project for those 
with more memory would be a routine to 
round off the results to two decimal places! 


Fa 


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31 


8K ROM 
2K RAM 


Keeping Time in the 


Home Office Chuck Dawson 


Since the Sinclair computers have an inter- 
nal timing feature, they can be used to make a 
clock display which will give you the time. 
Two basic programs are given below to do just 
that. 


A Digital Clock 

The first program provides you with a digi- 
tal clock. The display will show the time in 
digits about three inches high and extending 
all across the screen. 

Lines 130 and 140 control the timing. Line 
130 counts the number of frames sent to the 
television since the last PAUSE and then holds 
until a specified number is reached. The 
PAUSE in the next line is used to fine tune 
things and also reset the frame counter for the 
next minute’s cycle. 

If your computer is capable of SLOW 
mode, you will see a display which stays rock 
steady until a minute passes and the last digit 
slowly changes itself into the next appropriate 
number. In the SLOW mode it does not always 
take exactly the same amount of time to up- 
date the display. I have noticed that, if the 
memory is nearly full, the computer seems to 
take longer to compute. 

In the FAST mode, this trick will not work 
since no frames are sent during the compute 
cycle. So change line 130 to a PAUSE 3288 
and line 140 to POKE 16437,255. The large 
numbers themselves are generated by PEEK- 
ing into the ROM’s own character generating 
routine and enlarging it eight times. For faster 
updating, only the middle six lines are used. 
There are blank lines above and below each 
character so there is no reason to waste time 
reproducing these. 

After you have typed in the program, use 
GOTO 700 to SAVE. The program will then 
run itself. 


Chuck Dawson, 6520 Victoria, Fort Worth, TX 
76118. 


32 


10 


Listing 1. Digital Clock. 


REM “DIGITAL CLOCK“ TO SAVE 


GOTO 7? 


iS PR 


23 


INT “ INPUT TIME“ 
INPUT TIME 


25 GLS 


3a. 
E-INT 


ET M=INT (TIME .18@) t6@+TIM 
iT IME + IGG} 100 


35 GOTO 148 


(a) 


138 
308 


LET T=0 
LET D=INT 
AOTER a 


CET = {INT {(M760)) -109D 
GOSUB 500 


CCINT (M760}} 718)? 


(6@e(M7EG-INT (M/ 
-INT (M710) £20 
IF PEEK 16437¢>245 THEN GOT 
PAUSE 1248 
LET M=M+i 
IF M=144@ THEN LET M=9 
GOTO 49 
=79@5+D2& 


ET EGN 

IF X<225 THEN GOTO 566 
LET €=12& 

LET X=X -128 
LET X=x*s2 
PRINT CHRE D: 
NEXT L 


PRINT TAE T; 


IF M=780 THEN LET M=62 
IF F=@ AND D-a THEN LET N=7 


Program 1. Digital Clock. 


TO S 
1 


The Face Clock 

The second program will give a display 
with the traditional face clock. The face is 
drawn only once and then the hands are 
PLOTed in and UNPLOTed when no longer 
needed. This program is suggested by an 


exercise in the chapter on time and motion in 
the ZX81 manual. 


Listing 2. Hand Clock. 
“FACE CLOCK" TO SAVE GO 
INPUT TINE 


1@ REM 
ae 

2 PRINT “ 
i4 INPUT T 
16 LET H=2seINT (T7186) 

16 LET T=T-1@@z2INT (tt /i8@) 
20 IF T>15 THEN LET H=ħ+ł 
22 IF 345 THEN LET H=H+1 


O=1 TO 12 
PRINT AT i18-162C05 


42 {(DsG2P IE) 
713410#5IN (D/s6#PI3;0 
50 NEXT D 


SLOW 
65 POKE 16437 ,258 
78 get 150 


GOSUB 18380 
120 LET T=T+i 
130 IF T=60 THEN LET 


lao IF Tote OR T=46 THEN GOTO 2 
Sa 
150 LET P=2 
16@ LET L=T/S@2PI 
170 LET X=27+1825IN Ł 
180 LET Y=22+264C0S5 L 
198 LET C=x 
200 LET D=Y 
220 GOSUE Sie. 
230 PEEK 16457>241 THEN GOTO 
238 
235 PAUSE 215 
248 GOTO 80 
250 LET H=H+2 
250 GOTO 24 
310 LET P=i 
320 LET a=37 
330 LET 6=22 
340 LET G=H7122PI 
35@ LET C=274222S5IN G 
360 LET D=22+12C0S 6 
370 GOSUB 1000 
380 RETURN à 
S00 SAVE “FACE CLOCK" 
S18 RUN 
1000 R=27F 
1@@2 LET 5=22 
1008 LET U=C-A 
1010 LET U=D-65 
1020 LET O=SGN U 
1938 LET L=SGN U 
1040 LET Z=SGN U 
1050 LET 9= 
10860 LET M=ABS U 
1070 LET N=ABS U 
1080 IF M>N THEN GOTO 1138 
1898 LET Z=0 
1100 LET 9=SGN U 
1110 LET M=ABS U 
1129 LET N=ABS U 
1140 LET S=INT (M2) 
1150 FOR I=@ TO M 
1160 IF P=i THEN PLOT A,B 
1165 IF P=@ THEN UNPLOT A,B 
1170 LET S=S+ 
438@ IF S:M THEN GOTO 1230 
1199 LET S=S- 
1200 LET A=A+6 
1210 B=B6+L 


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If you have only 2K RAM, you will find 
that this program fills up almost all available 
space. If you have a 16K module, you can add 
the second hand and other decorative touches. 

After you have typed in the program, use 
GOTO 500 to SAVE. The program will then 
run itself. 


Setting Your Clock 

In both programs, after the program is run- 
ning, you are asked to input the time. Do not 
use a colon; just enter the figures: Not 3:45 but 
345. 


Program 2. Face Clock. 


A Calendar 

From time to time we want to see how a 
certain month falls in the calendar or what day 
of the week a certain date is on. Most calen- 
dars show only one year on either side of the 
calendar year. Thus dates beyond the printed 
calendar have to be calculated laboriously by 
hand with the danger that we may have over- 
looked a day in an irregular month. This pro- 
gram provides the solution to the problem. 

With this program you can enter any month 
and any year, and the computer will show you 
the calendar for that month. Well, not exactly 
any year. It has to be between September 14, 
1752, and February 28, 2200. Nevertheless 
that range covers most dates of interest. 

After you have typed in the program, use 
GOTO 300 to SAVE. The program will then 
run itself. The prompts will call for inputting 
the month and year. Type in at least the first 
three letters of the month and hit ENTER; then 
type in the year and hit ENTER. The com- 
puter will then display the calendar for that 
month. You can use either FAST or SLOW 
mode but remember that it takes much longer 
to produce the calendar in the SLOW mode. 

To test whether the program is working 
right, tty DECEMBER 1941. We remember 
that the 7th was on a Sunday. Now try some 
other dates. Try your birth month and year. I 
use this program to plan business trips and 
vacations for the coming year even before I 
start getting those free calendars in the mail in 
December. 

This is a good program for showing off your 
computer to your friends. Try it at your next 


party. 


Program 3. Calendar. 


JANUARY 1933 


SUN MON TUE VED THU FRI SAT 


6 
13 


FER agaa 


TUE WED THU FRI 
4 
TI 
13 
25 


FEB 399999 


MON TUE WED THU FRI 
1 = 3 4 5 
8 3 109 12 12 
15 16 iL? L& 19 

24 25 26 


Listing 3. Calendar. = : 
S REM “CALENDAR. FO ARIE SeTo 
saa 


kae 


10 LET As="CDOUANFESMARAPRARY UU 


NUL RAUGSEPOCTNOQUDECSUN MON TUE W 
Ee ae FRI SAT 


INPUT MONTH’ 


25 FOR M=1 FO 12 
3S@ IF BSili FO Bi =AS (34M FO 33M 


S@ INFU 
SS F Y11752 THEN GoTe se 
6a Lo ; 


ee tè s zg . ve Pt e 
120 IF 3<2@ THEN PRINT " "; 
130 I NO 33-PEEK 16441-7 
x4 THEN sTar 


@ IF PEERK 126441=5 THEN PRINT 


i50 NEXT I 

200 LEF xX=8 

210 IF M=1 OR M=2 THEN LEF X=1 
220 LET L=¥-X 

230 LET X=H+x#12e 

240 LEF P=INT (L71002? 

250 LET 2Z=INT (2134 (%32) 7S5} + INT 
(SELA? AINT (Prd) -P 

260 ae OE CERA 


URN 
3@@ SAVE “CALENDAR” 
310 RUN 


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8K ROM (4K ROM) 
1K RAM 


Calculating the Days 


Ronald Paludan 


Knowing the number of days between 
two dates is frequently necessary for cal- 
culating interest, apportioning expend- 
itures, or calculating average use of items. 
We are also interested in the more trivia 
type questions such as how many days 
before an important date, how many days 
between certain historical dates, and even 
how many days we have lived. 

This program will enable you to deter- 
mine the number of days between dates 
either for serious use or just curiosity. 
The program in Listing 1 is for the 8K 
ROM machine with 1K RAM. A 4K ROM 
adaptation is included in Listing 2. 


Operating Instructions 

1) Type in the program in Listing 1. Hit 
RUN and ENTER. 

2) The prompts will ask the user to 
ENTER FIRST DATE. Do so in this 
order: Type in the month as a number 
from 1 to 12 and hit ENTER. Type in the 
day of the month and ENTER. Finally, 
type in the year giving all four digits and 
ENTER. 

3) Repeat this process for the second 
date. The first date must be earlier than 
the second. On the 4K ROM the two 
dates cannot be more than 88 years apart, 
but a method is supplied for dealing with 
this problem. 

- 4) The answer will then be given on the 
screen. 

5) To repeat, hit ENTER. To quit, hit 
any number or letter and then ENTER. 


Error Checking 

The input routine does not allow the 
user to enter more than 12 for a month or 
31 for a day. The user with enough mem- 
ory may want to add a more detailed 
error checking routine that rejects non- 
existent dates, e.g., June 31. 


Modifications for the 4K ROM 

Listing 2 gives the lines which must be 
altered to allow the program to operate 
properly on the 4K ROM (ZX80 or 
MicroAce). 


4K ROM Problem: Dates more than 88 
Days apart 

The integer Basic of the 4K ROM ZX80 
will not handle numbers greater than 
32767. For this reason, the program will 
reject the second year if it is more than 88 
years after the first. However, there is a 


Ronald Paludan, 3730 N. Oracle, 41, Tucson, AZ 
85705. 


36 


method for finding the number of days 
between two dates more than 88 years 
apart. This method requires the use of 
one or more mid-date(s) which must be 
less than 89 years from the date next to it 
in the series. The number of days between 
the first date and the mid-date is com- 
puted and the results recorded. Then the 
number of days between the mid-date 
and the second date is computed and 
added manually to the first result. 


Listing 1. 

Days between Two Dates (8K ROM). 
20 DIM N12? 
25 LET Nii)= 
3@ L N€2) =31 
35 LET N(S) 259 
4@ CET Ni4) =98 
45 LET N(5) =120 
So LET N(6} =151 
SS LET Nt7)=181 
6@ LET N(S3 2212 
6S LET N(9)} =243 
7@ LET NC1@) =273 
7S LET N11) =Se@4 
Se L N(12) 2334 
aS LET D=09 


U 
D 
e 
a 
z 


1428 PRINT “ENTER FIRST DATE: “i 
Lið INPUT M1 

ii2 IF Mi>12 THEN GOTO 118 

129 PRINT Hi; “7"; 

i3@ INPUT D1 

i132 IF INT Bi: Bh a GOTO 1308 


¥2 
170 PRINT “ENTER SECOND DATE: " 


INPUT M2 
185 IF Me>12 coe GOTO 180 
iS@ PRINT Me; 

200 INPUT D2 

2835 IF D2>%31 RARR GOTO 20@ 

210 PRINT D2“ 

20 INPUT Y2 

225 IF Y2-Y1>86 OR Ye<Y1i THEN G 
OTO 220 

238 PRINT Y2 

248 FOR x=y'1 Ze Ya-1 

250 LET D=D+3 


255 IF INT a eas cea AND IN 
T (X740@) £40@<X THEN GOTO 265 
=e IF INT (X-4} £4=X THEN LET D 
=O + 

255 NEXT X 

2709 IF Yiz=Y2 THEN LET D=36S-D 
275 IF INT (Y27100? £16@8=Y1 AND 
INT (¥174@006) 24808@<Y1 THEN GOTO 28 


280 IF INT tYivdai} #4=-Yi AND Mi>2 
THEN LET D=D-1 
265 IF INT (t¥27169} £186=Y2a AND 


ae Cf274G8}3 EAO THEN GOTO 3E 


290 IF INT (Yera)} #4=Y2 AND M2>2 
THEN LET D=D+1 

389 LET D=D-NiM1} -Di 

318 LET et ey ee 


S38 IF YS="" THEN GOTO 2¢ 


Listing 2. 4K ROM Adaptations. _—_—_—_— 


299 IF 100%*(X/100)=X AND 400k (xX 
4490)<X THEN GO TO 265 

260 IF 4*(X/4)=X THEN LET D=D+i 
2790 IF Yi=Y2 THEN LET D=D-365 
2735 IF 100*¢(Y1/100)=Y1 AND 400% 
(¥1/400)<Y1 THEN GO TO 285 

280 IF 4*(Y1/4)=Y1 AND Mi?2 THE 
N LET D=D-1 

285 IF 100k*¢(Y2/100)=Y2 AND 400% 
(Y2/400)<Y2 THEN GO TO 300 

2970 IF 4x¢(Y2/4)=Y2 AND M232 THE 
N LET D=D+1 


SEa Delete 


As an example of how this method 
works, lets calculate how many days 
apart July 7, 1881, and January 1, 1981 
are. 

ENTER FIRST DATE: 7/7/1881 

ENTER SECOND DATE: 1/1/1921 

(mid-date) 
14423 DAYS APART 


(ENTER) 


ENTER FIRST DATE: 
(mid-date) 

ENTER SECOND DATE: 1/1/1981 
21915 DAYS APART 


1/1/1921 


14423 
+21915 


36338 Days apart 


Variables Used 

N(n) Days used in year by nth month 

D Day counter (Number of days 
between dates) 

M1 Month of 1st date 

D1 Day of month for 1st date 

Y1 Year of 1st date 

M2 Month of 2nd date 

D2 Day of month for 2nd date 

YZ Year of 2nd date 

X Temporary variable used 
as counter 


Routines 

The routines are found at the following 
lines: 

20-85: Initialization. 

95-230: Input dates. 

240-310: Count days between dates. 
Compensate for leap years. 

320: Print results. 

330-340: Input “”to repeat. 


Examples 

The American Civil War lasted from 
February 8, 1861, to May 26, 1865. How 
many days did it last? 


ĦrD/Y 
ENTER FIRSF DATE: 27371361 
ENTER SECOND DATE: 572671855 
1566 DAYS APART 


John has a report due on July 20, 1982, 
and today is May 15, 1982. How many 
days does he have to complete the 
report? 


MDY 
ENTER FIRST DATE: 5721571982 
ENTER SECOND DATE: 772071982 
5S DAYS APART 


Herb was born on August 1, 1945. How 
many days old will he be on his 40th 
birthday? 


MDY 

ENTER FIRST DATE: 8r2+12945 
ENTER SECGNGE DOATE: Sriseisés 
146108 DAYS RPART 
Be ay aa OS EIA me Ps E Se eT 

Fo SY 
27371988 
47171988 


ENTER FIRST DATE: 
ENTER SECOND DATE: 
31 DAYS APART 


MDY 
INTER FIRST DATE: i7i/1979 
=NTER SECOND DATE: 47/1/1979 a 
33 DAYS APART 


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38 


8K ROM 
1K RAM 


Tidying Up Your 
Display Nick Godwin 


A list of numbers is conventionally written 
down aligned on the right. This poses a prob- 
lem on the ZX81, which lines numbers up the 
left. 


Handwritten ZX81 display 
96 96 
920 920 
eS. A 
1020 1020 


A routine to print, display, and summate a 
series of values may look as follows: 


118 LET T=9 
120 FOR J=1i TO 18 
uT A 


The problem is, how to change the ZX81 dis- 
play to conform to normal convention—how 
to align the values to the right. 

The following amendment to the above 
does the trick, for integers (positive or nega- 
tive) only: 


STOP 
1010 PRINT TAR 17-LEN X$;X$ 
1020 RETURN 


The routine prints the values neatly in the 
middle of the screen. However, it is very likely 
that you may want to print out decimal values 
in a similar format. The following subroutine 
(replacing the one above at line 1010) does the 
trick: 

1010 IF X#(1)="." THEN LET X$="@ 


XE 
1820, IF LEN X€> ae IF X$(1i TŪ 
2} ="-.“ THEN ter XG="-B"“+4+XEl(S T 


1230 FOR K=1 TO eg aa 


19840 IF Eef {K} = TH GOTO 1872 
1850 NEXT 
i360 LET xex $t“ 


1978 PRINT TAS ESE x 
1886 RETURN 


Nick Godwin, 4 Hurkur Crescent, Eyemouth, 
Berwickshire, Scotland TD14 5AP, United 
Kingdom. 


To test this routine, RUN the program and 
enter a series of wildly different values, e.g.: 
46 
9.009 
-34456789.98765 
-0.0000002 
.0000034 
8.6 
88888.97 
9999999 
.01 
.09 

In practice, you will be fairly unlikely to 
require such a wide range of values for addi- 
tion purposes, but the routine works equally 
well for any kind of arithmetical manipula- 
tion, or for any other list of numbers. 

It may well be that you require the program 
to add sums of money, in which case you will 
want displayed only the value to two decimal 
places (representing pence or cents). To 
achieve this, the routine can be amended by 
adding or changing the following lines: 


110 LET ¥F=a 
120 sur a =i FO 186 


EF X= 
180 GOSUB ieee 
399 STOP 
pre LEF X#$=STRS (INT {X4100+.5) 


iaia IF X#$t1)="." FHEN LET X$="0 


4s X$>1 THEN IF Xsti TO 


1020 IF L 
2) =," LET <$="-@"°+xg fa TF 


o 
1030 FOR K=1 TO LEN X$ 


104@ IF LM IK} ="." THEN GOTO 1072 

1350 NEXT 

10250 LET TENIR 
LEN 


ga” 
onl a K= X$—2 THEN LEF X$=X 


PRINT TAB 17-K;X$ 
ieee R RETURN g 


This routine prints the values neatly dis- 
played in the middle of the screen, with the 
decimal points at TAB 16. The display routine 
does not affect the arithmetical calculation: 
you can enter as many digits as you like after 
the decimal point, and for the display they will 
be rounded to the first two decimal places. 
The lateral position of the display can be al- 
tered by adjusting the number (17) in line 
1080, but care must be taken to allow for extra 
long numbers. The bug is that a value of .005 
(half a pence or cent) prints as 0.00, not very 
serious, and probably not worth the bytes re- 
quired to correct it. 

The program as written occupies 394 bytes 
of RAM, 486 including the variables, and ap- 
proximately 890 bytes including the display. 
Thus it is operational on 1K. The subroutine 
alone occupies 268 bytes. 


SYNC Magazine 


8K ROM 
1K RAM 


Multisave 


Doug Watson 


Reliability of cassette storage and retrieval 
of programs and data requires multiple saves. 
Having to attend to the computer’s needs as 
each save is completed is, however, a bit of a 
chore. 

Wouldn’t it be nice 

1) to key in the number of saves required 
and leave the ZX81 to complete that number of 
identical copies? 

2) not have to check what variables have 
been assigned before incorporating this fea- 
ture in a program? 

3) to retain the normal, single-save mode? 

If this appeals to you, try the demo program 
shown. The address shown as 16004 can be 
any unused, non-saved address in RAM (such 
as from 8192 to 16383 with the 64K Memopak 
or above RAMTOP) that is normally 0. PEEK 
it to find out. 


5 REM “PROGRAM NAME" 
1@ PRINT AT 5S.6:"2 + = PROGRAM 


= 
20 PRINT a“ FOR MULTIPLE S$ 
NT ssa“ FOR SINGLE SAV 


~ 
ko 


189 PRINT “HON MANY SAVES?" 
119 PAUSE 48600 
120 aoc ge 165@7,VAL XINKEY §-1 


150 SAVE “PROGRAM NAME" 
siara TT SLOW OR FAST HERE IF DE 
170 IF PEEK 16507-09 THEN RUN 
190 POKE 16507; PEEK 16507-1 
438 GOTO 150 


= * ų PROGRAM * * + 


FOR MULTIPLE SRUES, GOTO 108 


FOR SINGLE SAVE, GOTO 150 


On GOTO 100, HOW MANY SAVES? ap- 
pears on the screen and waits (no L cursor). 
When one of the keys, 1 to 9, is pressed, the 
selected number of saves will be executed. If 0 
is pressed, 256 saves will follow. Use BREAK 
to terminate. 

On GOTO 150, a single save is executed. 

No variables are used so compatibility with 
any program is automatic. 


Doug Watson, PO Box 142, Barry’s Bay, Ontario, 
Canada KOJ 1B0. 


January/February 1983 


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Making Backups for 
Machine Language 
Tapes Jack Ryan 


Not long ago I bought a cassette of utility routines for my 16K 
ZX81. Although the routines on the tape were just what I needed, 
there was one problem: the program was in machine language and 
once LOADed above RAMTOP it ignored my SAVE commands. If 
something happened to that tape I was out of luck since I had no 
backup — unless I could make one by some method other than 
SAVE. 

There are two methods which can be used to make a backup. 


1. Copying to a Second Tape 

The first technique is to simply copy the tape onto a second tape. 
This requires either a tape copier or a second tape recorder. 

Place the original tape in Recorder | and a blank tape in Recorder 
2. Use one of the Sinclair recorder leads to connect the earphone 
(output) jack of Recorder | to the microphone (input) jack of Re- 
corder 2. Set Recorder 2 to RECORD and PAUSE, and (if it has one) 
the automatic level control (ALC) to OFF Set the volume controls of 
each recorder to midrange. Start RECORDing on the second, then 
PLAYing on the first. After the recording is complete, try LOADing 
the program as usual with your recorder. Very likely you will have to 
try several different volume settings on your copying set up before 
getting a LOADable copy. A recording level meter on Recorder 2 
helps. I found that I could not get a satisfactory recording without 
the ALC of Recorder 2 OFF 


2. Copying with PEEK and POKE 

The second technique uses the PEEK and POKE facilities of the 
ZX81. The program to do this is Listing 1. Like the machine lan- 
guage routines that you see published, the software that I purchased 
is LOADed into memory above RAMTOP. RAMTOP is the address 
of the first nonexistent byte at the upper end of memory, which 
means that you cannot store anything at or above it—at least that is 
what the computer thinks. However, the address of RAMTOP is 
stored in the two bytes with addresses of 16388 and 16389. You can 
change these two bytes with POKE, and fool the computer into 
thinking that some existing memory is nonexistent. This memory is 
hidden from Basic and so is protected for machine language use. 

PRINT PEEK 16388 + 256 * PEEK will tell you the address of 
RAMTOP, which is normally 32768 with the 16K RAM attached. 
The bytes stored at 16388 and 16389 (found by PEEKing each 
location) are 0 and 128. Note that 0 + 256 * 128 = 32768. Before 
loading a machine language tape, one or both of these bytes are 


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Listing 1. 
4 FAST 
Sa PRINT TAB 7i "ML PROGRAM BAC 
Ga 


PRINT 
FO REM “ENTER PRRAMETERS FOR Y 
eer ae gh R 


5 RINT NTER THE NUMBER TO 
BE POKED" i 
9@ SRINT TAB 1@; “INTO 16386",, 
LØG PRINT TAB 7; “IF NONE., ENTER 
11@ INPUT A 
120 JLS 
150 PRINT “ENTER THE NUMBER TO 
BE P Å. $ 
PRINT TAB 10; “INTG 16389 
ise PRINT TAG 7; “IF NONE. ENTER 
169 INPUT B 
126 PRINT “ENTER YOUR NORMAL RA 
TOP 
M OO PRINT “(17408 FOR 1K, 32768 
FOR LENy * 
200 INPUT R 
240 CLS 
520 REM “C = NUMBER OF BYTES PR 
OTECTED“ 


230 LET C=R-{A+256 r6? 
240 SA = LAST BYTE BEFORE N 


258 LET D=(At25646) -1 
260 REM “STORE MACHINE LANGUAGE 


IN E 
DIM ECC 
FOR N=1 TO C 
LET a ols =PEEN (tO+<4Nnr 


“PUT ML ABOVE RANMTOP™ 
N=2 TO C 
ribi E tiNI 


370 SAVE “PY 
0330 


changed by POKEing in new values to give RAMTOP a new, lower, 
address to correspond to the number of bytes required for the ma- 
chine language routine. For example, the software I purchased 
comes with instructions to POKE 16389,124. So RAMTOP is now 0 
+ 256 * 124 = 31744, a difference of 32768 — 31744 = 1024 bytes. 
If you had a program with instructions to POKE 16388,100 and 


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POKE 16389,125, then the new address of RAMTOP is 100 + 256 * 
125 = 32100, and the number of bytes protected is 32768 — 32100 
= 668. 

To make a copy of your machine language software, LOAD the 
program according to the instructions which accompany it. Then 
ENTER or LOAD the program in Listing 1. RUN the program and 
ENTER the requested data. Because the program runs in FAST, the 
screen blanks out while the program PEEKs the machine code into 
the variable array E. When the program stops with 9/310, prepare to 
SAVE the program. To SAVE, enter GOTO after you have begun 
recording. When you LOAD this SAVEd tape (LOAD “P”) after 
altering RAMTOP as your machine language program requires, it is 
self-RUNning so the screen will blank out while the code is POKEd 
in above RAMTOP. 

If you want to SAVE a copy of Listing 1 without any machine 
language code so that you can LOAD it in for a variety of machine 
language routines, enter SAVE “P”, not GOTO 370. 

The program as shown in Listing | is meant to be self document- 
ing and user-friendly. But this is not necessary for operation of the 
program. Since this probably makes the program too large for a 1K 
machine, and makes it take longer to LOAD in any case, you might 
want to shorten it a bit. You can easily calculate the new address of 
RAMTOP and the number of bytes protected. So you could easily 
eliminate all REMs and replace lines 10 through 260 with 

10 FAST 

20 LET C = (calculated bytes protected) 

30 LET D = (calculated new RAMTOP ) — 1 

In summary, you can make back up tapes for machine language 
routines which are LOADed above RAMTOP by copying your orig- 
inal tape from one recorder to a tape in a second recorder, or you can 
use a Single recorder and the Basic program in Listing 1 to PEEK out 
the code for SAVEing and POKE it back in when LOADing from 
your back-up tape. a” 


41 


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INTERP — The Kernel of Interactive Nuts 


Lawrence Auer 


In this article we present an easily ex- 
tended, interactive interpreter, providing a 
stack oriented, dictionary based program- 
ming environment similar to FORTH. The in- 
terpreter is, thus, the basis for the more 
friendly, more interactive use of your com- 
puter. The ease with which INTERP can be 
coded is a dramatic demonstration of the 
power of the ZX81 string manipulation 
capabilities and the GOSUB and VAL 
commands. 3 


Interaction 

The essence of effective use of the personal 
computer is contained in the word, “interac- 
tion.” While more memory and languages are 
desirable to have, solving problems with a 
computer is essentially a function of how easy 
it is to control the machine. A computer is 
able to perform simple tasks like adding one 
and one, or recalling what the balance is in the 
checking account, or integrating a set of dif- 
ferential equations. What it has trouble with, 
and what humans excel at, is decision making 
and recognition of the significance of a result. 
(Computers are just as happy with a balance 
of -$1.00 as +$100,000.00) Thus, a proper 
man-machine dialogue might have the form: 

Man: What would happen if... .? 

Machine: !!!!!!! (a result unexpected or un- 
desired by Man) 

Man: Well then, do this first: ..... 

Man: And then, do this:.... 

Machine: ..... Hmmm 

Man: Given that, what would the further 
consequences be? 

Machine: ....... 

Man: Thanks. 

Any program which inputs data and per- 
mits decisions on the basis of the input is, of 
course, interactive. The operationally impor- 
tant point is that in normal programs, the con- 
trol is quite limited. The flow of code is re- 
stricted. Control cannot be arbitrarily trans- 
ferred from one place in a program to another. 
Humans do not normally suffer from this re- 


Lawrence Auer, 1202 Seventh St., Los Alamos, 
NM 87544. 


January/February 1983 


striction. They can do their operations in 
whatever order is most convenient. The pur- 
pose of INTERP is to provide the basis of a 
“General Interactive System” of maximal 
flexibility. 

The features required in an interactive sys- 
tem can be seen in the following simple exam- 
ple. Consider a program to keep track of 
where you are spending your money. Inputs to 
your program are the amount and the type of 
each expenditure. We leave the details of the 
coding as a problem for the reader, but a typi- 
cal interactive session with a program based 
on INTERP could be 

? 

225.00 RENT 

42.27 FOOD 

9.25 CLOTHING 

2*0.90 3*0.65 + 0.45 + , FOOD 

EXPENDITURES 

CLS 

... More entries... 

EXPENDITURES 

STOP 

The general features and requirements 
demonstrated by this example are as follows: 

1) The interactive system is composed of 
individual modules or “‘primitive opera- 
tions.” In the above example, “EXPENDI- 
TURES”, lists the totals so far in each cate- 
gory, while “RENT” adds the amount indi- 
cated to the category rent. Each module has a 
well-defined input and output. They share 
data but their actions are accomplished by 
separate pieces of code. 

2) Except for obvious dependencies like 
initialization, the order in which the modules 
may be invoked is arbitrary. 

3) The simplest way to call up a module is 
by name. It is both more easily remembered 
and more reliable to use “RENT” than to 


choose this operation by number from a 

menu, which is the typical method employed. 

4) There must be a general way of passing 
values or “arguments” to and from the mod- 
ules. The result of an operation need not be 
printed, but it should be easily available. In 
other words, we want the equivalent of 
“named subroutines”. 

5) Modules like “RENT” or “FOOD” are 
obviously problem specific, but some opera- 
tions are of such general utility that they will 
be needed in most programs. The general 
purpose modules which are built into 
INTERP are: 

? — Output the names of the modules de- 
fined in the dictionary. 

: — Output the value at the top of the 
stack (see below for a discussion of 
stacks). 

— Output the top element, then remove 
it from the stack. 

Stop —Stop the program (SHIFT A), 
CONT will restart with no loss of 
results. 

CLS —Clear the screen; note this is the 
three letters C L S. 

All Basic functions, e.g., RND or PI any var- 

iable used in the Basic code, e.g., S or D, or 

any arithmetic operator, e.g., ** or/, are legal 
and usable. 


Basis of INTERP 

The key element of our implementation of 
these ideas in INTERP will be the use of 
BASIC SUBROUTINES. A subroutine is 
simply a block of code which is called via the 
GOSUB command. Control is transferred to 
the line number given in the GOSUB call, as 
in a simple GOTO. The important difference 
is that subroutines remember from where they 
were called. When a RETURN command is 


43 


encountered control returns to the line follow- 
ing the GOSUB which invoked the sub- 
routine. Conceptually, a GOSUB command 
amounts to telling the program to “go per- 
form a series of commands and then come 
back when you are done with them.” This is 
exactly what we want for a module. 

For anyone accustomed to programming in 
languages such as Pascal or Fortran, the most 
fundamental deficiency in the ZX81 Basic is 
that subroutines are not named. While 
GOSUB 700, for example, can be executed 
interactively and may cause the data to be plot- 
ted, humans are more at ease with typing 
“PLOT” in order to accomplish that task. We 
clearly cannot change the definition of the 
Basic language, but what we can do is make it 
easier for a user to get at pieces of the code. 
That is, through INTERP we add another level 
of code which “interprets” the input. Via 
INTERP we expand the Basic vocabulary so 
it includes whatever operations we require. 

The basis of the ability of INTERP to pro- 
vide named subroutines is its dictionary, 
which consists of the names of the routines, 
stored in the string array, D$, and the defi- 
nitions, which are nothing more than the line 
numbers with which the Basic subroutines 
Start, stored in the array, D, in the same order 
as the words in D$. Because the order is the 
same, the elements of the two arrays are re- 


lated when they have the same subscript. For 
example, D$(3) is the name of the third mod- 
ule, while D(3) is the line number where the 
third module starts. INTERP determines the 
meaning of an input word, W$, by scanning 
through the dictionary looking for the value of 
the subscript, J, for which W$=D$(J). Once 
the subscript is known, GOSUB D(J), exe- 
cutes the indicated subroutine. In other 
words, the dictionary gives a name to a line 
number. Of course, the block of code starting 
there must be a true subroutine, i.e., termi- 
nated by RETURN. 

Central to the operation of INTERP is the 
concept of a “stack,” which is just the math- 
ematical analogue of a pile of dishes on a 
spring-loaded dispenser at a cafeteria. Put a 
dish on the stack, and it “pushes” the stack of 
dishes down one level. Take a dish off, and it 
“pops” the stack up one level. The mathemat- 
ical stack is just an array of numbers with a 
pointer to the location of the current “top of 
the stack.” The basic rule in “stack process- 
ing” is that an operator always works on the 
elements at the top of the stack. The stack 
provides the logical organization for perform- 
ing a series of operations. Say we want to 
evaluate 

ERFC (FUNC(PI+7)) 
In our stack system we would re-write this as 
PI 7* FUNC ERFC 


The PI and 7 are values placed on the stack. 
The + removes the two top stack elements, 
adds them, and puts the result back on the 
stack. FUNC and ERFC simply get their one 
argument from the stack and replace it with 
the appropriate result, ready for the next 
operation. 

An operation always consists of removing 
the arguments used by the function from the 
top of the stack and leaving the result gener- 
ated as the new top value. While the standard 
mathematical operators have either one or two 
arguments and return one value, user-defined 
functions may have as many arguments as 
needed and return an arbitrary number, up to 
the limit defined by the size of the stack. 


Implementation of INTERP 

Our interpreter consists of the following 
steps: 

1) Get a word of input (GOSUB 200) 

2) Is the word in the dictionary? 

IF W$=D$(J) THEN GOSUB D(J) 

3) If not found, then: 

If the word is a Basic operator, apply it to 
the stack. 

Otherwise apply VAL to it and put the result 
on the stack. 

4) Go back to (1) for more words. 
This is a fully general interpreter. As a side 
benefit, it is also a “Reverse Polish Com- 
puter” which can be used in the same way as 
an HP calculator. 


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SYNC Magazine 


While one could require that each word be 
terminated by NEWLINE, it is much more 
friendly to permit “type ahead,” that is, to 
allow the input to be as long a string as the user 
wishes. Words are then extracted from the 
input string by using internal spaces as de- 
limiters. This is particularly convenient, 
since we permit arguments to be associated 
with subroutine calls. For example, 

3 ERFC. 
is easier to type and understand than the to- 
tally equivalent, 

3 

ERFC 


When the input line has been completely pro- 
cessed, INTERP prompts for further input by 
printing, “OK”. 

The division of the line into words is done 
in the code starting at line 240. Note that the 
code starting at line 300 “‘hashes’ ” the word 
being input. This hashing technique only af- 
fects words which are longer than four charac- 
ters. It is done so that words of any length may 
be put in the dictionary without having to pay 
too high a storage cost. When strings are di- 
mensioned, say DIM D$(20,4), the maximum 
number of characters in each D$(I) is the sec- 
ond value in the DIM statement. Thus, one 
could never store the string, “SOLVE”, in this 
array. LET D$(1) =“SOLVE” is legal, but 
results in D$(1) containing only “SOLV”. 
Thus, we hash the word by storing its first 


four characters, and then changing the fourth 
character to be the length of the word if it is 
longer than four characters. The effect is to 
reduce the length of all words to just four 
bytes, but to maintain distinction among 
them. For example, “SOLVE” becomes 
“SOL5”, while “SOLVENT” becomes 
“SOL7”. This hashing scheme must be rec- 
ognized when extensions are made to the dic- 
tionary. The word, “SOLVE”, is made the 
seventh word on the dictionary by adding be- 
fore line 90, LET D$(7)=“SOL5”’ 
and changing the value of D, set in line 90, 
accordingly. 

Note, how we use the CHR$ function in 


line 310 to generate the character correspond- 


ing to a numerical value. Since “O” is the 
28th character in the ZX81 character set and 
the digits are stored in ascending order, 
CHR$(28+N) generates the symbol corre- 
sponding to the number N. If N=10, 11,..., 
the characters generated by this algorithm are 
A : 

The code starting at line 500 is used to eval- 
uate expressions and is based on the ex- 
tremely powerful ZX81 function, VAL. This 
operator, when applied to an arbitrary string, 
produces the numeric value defined by the 
string. For example, if the Basic variable 
X=O, the expression VAL “COS X” has the 
value 1. VAL permits the input to contain any 
BASIC expression which does not contain an 
explicit space. Expressions may also be en- 


tered in the “Reverse Polish Notation” natural 
to INTERP, although then each operator and 
term must be delimited by spaces. The point 
is that the type ahead feature uses spaces as 
delimiters. ‘‘2**3”’, for example, which con- 
tains no spaces, is treated as a single expres- 
sion. Since it is not found in the dictionary or 
recognized as an operator, it is evaluated by 
VAL and the result, 8, put on the stack. The 
input, “2 3 **”, where the symbols are sepa- 
rated by spaces, is split and each term treated 
separately. The “2” and “3” are individually 
evaluated by VAL and the corresponding nu- 
merical values put on the stack. Then 
INTERP recognizes “**” as a binary opera- 
tor and, as described below, creates a string 
and then applies VAL to it the top two ele- 
ments of the stack, replacing them with 8. 

Strings containing operators are easily 
created. Almost every symbol appearing on 
the keyboard, with the exception of keywords 
like PLOT, UNPLOT, etc., which are white 
and above the keys, can be entered by a single 
keystroke. Thus, to enter the word STOP one 
needs only type SHIFT A; a call for the SIN 
operator is FUNCTION Q, and so on. Note, 
that even though the ZX81, when it prints 
these words, adds spaces of its own, they must 
be delimited by true spaces when being input 
to INTERP. 

The hashed input word is compared with 
the dictionary in the loop starting at line 410. 
If it is found, the corresponding subroutine is 


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executed. If not found, at line 500 it is 
checked to see whether the unknown word is 
actually a Basic operator. Finally, if still un- 
recognized, INTERP concludes that the word 
must actually be a Basic expression and goes 
to line 600 to evaluate it. The result produced 
by VAL is stored in the stack vector, S. If a 
typing error was made, the word entered will 
be meaningless to INTERP and an error will 
be signaled. If this happens, the user can con- 
tinue without any loss of the computations 
already made by entering GOTO 100. 

In order to apply W$ as a Basic operator, 
we must make one further judgment: is W$ a 
binary operator, like +, or a unary operator, 
like SIN? This is decided in line 510. The 
expression to be evaluated is constructed by 
String concatenation in lines 550 (binary 
operators) and 570 (unary operators). The 
values used are replaced on the stack by the 
value generated. We see here how by using 
VAL and string manipulation one can create at 
run time the equivalent of Basic program 
statements. 

The stack in INTERP has been im- 
plemented using the array S(). The pointer to 
the top is the value of variable S. The top value 
on the stack is, therefore, S(S). Whenever the 
stack is manipulated, the value of S must be 
changed accordingly. For example, when one 
does a binary operation, as in lines 540-550, S 


is reduced by one. Any user subroutine which 
requires arguments should check that there 
actually are as many elements on the stack as 
will be needed. If S is less than the number 
that are needed, GOTO 9990 will generate an 
appropriate error response. 


Simple Example: A Reverse Polish 
Calculator 

As an example of how one adds new 
routines, let us produce a program which 
models a simple HP-like calculator. Because 
calculators are clearly interactive, INTERP is 
our natural starting point. We already have all 
the mathematical functions, so in order to 
create our calculator program, all we will 
need to add are a few operations for manipu- 
lating the stack: 


DUP — Duplicate the tope element, i.e., 
push this value again onto the 
stack. 

SWAP  — Interchange the top and next 


elements on the stack. 

ROTATE —Rotate the order of the stack 
elements. 

STACK — List the values on this stack, top 
first. 


Figure 1. 


equivalent to PRINT SQR(3*3* =4*4) 
will print .5 and 2 
equivalent to PRINT 1*2*3*4 


3 DUP * 4 DUP * + = SQR. 
12/,1SWAP/. 
1234***, 

STOP 


The code for including these four new words 
is given in the second listing. The important 
points to note are: 

1) The new definitions in the dictionary 
must be made before line 100, the start of the 
interpreter. 

2) If a name is longer than four letters, like 
ROTATE, it is stored in D$ by its first three 
letters followed by its length, “ROT6”’. 

3) Each subroutine must be terminated by a 
RETURN. 

4) Routines should check that there are an 
adequate number of arguments on the stack. 
If there are not, the transfer GOTO 9990 will 
indicate the error. 

If you are not familiar with the reverse 
Polish system used on HP calculators and in 
INTERP, it would pay you to enter the state- 
ments of the second listing and then to try it. 
One very important thing to note is INTERP 
DOES NOT AUTOMATICALLY OUTPUT 
ANY RESULTS. In order to see the result of a 
calculation you must use either the command, 
,**, which will print the answer, or “.“, 
which prints and then discards the top of the 
stack. Typical calculations would be found 
in figure 1. 


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Remember, the words and numbers can be 


___s Listing 2. RPN Calculator. 


entered using as many lines as you wish. 2) Whenever you wish to create a program, 1 REM RPN_ CALCULATOR 

In passing, we should note that, while © LOAD INTERP. oe PES Bates coun 
INTERP permits arbitrary length words, your 3) Modify it, coding the various Basic SR LET Bie: ose 
fingers may not appreciate this. Thus, you routines you need. Terminate each by RE- oe ee ets) o nore 
will probably want to use “ROT” instead of | TURN and make sure it properly adjusts S. ee ret e 
“ROTATE”. To be entirely general, you can 4) Extend the dictionary, by adding new eo oe eee 
include both forms in the dictionary asthereis values to D$() and defining DQ) accordingly. A039 OEM Br. care 900 
no requirement that a given Basic module The variable D, defined in line 90, is the 3020 LET S(S) =5(S-a) 

~~ 


have a unique name. 


length of the dictionary. 


| REF 
REM SWAP 


5999 
i 5100 IF 5:2 THEN GOTO 2990 
| 5) SAVE your new program. The important S110 LET TMP oats) 
General Use of INTERP point is that, although the code in Listing 1 is 5120 LET $(5)=S(5-1) 
; : 5130 LET S(S-121) =TMP 
In itself, INTERP solves no problem; it long, it need only be entered once. Afterithas 3140 RETURN 
; : : 5199 REM ROTATE 
only provides a framework which can be used been stored on tape, it can be loaded and the 520@ IF S<2 THEN RETURN 
; ; ; ; 5210 LET TMP=S 15) 
to ensure that the code will be simple to use. needed routines easily added. S220 FOR IzS TO 2 STEP -1 
The steps that should be taken in employing We hope that you, too, find that INTERP is 524% NEXT I ages 
INTERP are: the best starting point for the creation of in- 3260 RETURN ous 
1) Enter and save the basic INTERP pro- _teractive programs. As it is a different ap- 3500 FoR tis To 1 STEP -1 
gram given in Listing 1. proach from the typical one, at first, coding 3336 Nexr reo! 
may feel strange, but the ease of its use will $330 RETURN 


Listing 1. INTERP. -——————- 
INTERP 


S=0 

eS Banani DEPTH IS 16 
REM TO MAKE DICT IONSRY SIZE 
Se eta a Cs OND D 


Wt Weague 
© 
Ki 
T 


10 LET 


an wa 


Piri HR I 


525 
DE USER DEFINITION 
TS NUMBER OF WORDS IN 


$D) =" STOP `“ 
iD) =1500 

38 LET | ee 

99 REM INTERPRETER 


GOSUB 200 
GOSUB 408 


ee 

H 

g 

k 
rogo 9 
u= Ol 


È. 
FOR L=1 TO LEN L$ 
By acre NEXT bt 


300 LET H=" “3 ¢ TO &} 
: IF ea ut t “THEN LET H@t4} = 


RETURN . 

399 REM SEARCH DICTIONARY 
GOSUB 300 , 

41@ FOR J=1 TO D 

4293 lie HE=ODEt(I} THEN GOTO 658 


XT J 

499 REM OPERATOR 

S0 IF LEN W222 OR WE<">" OR WS 
»"<e>" OR HEC'SIN “ AND govs“ TR 
EN GOTO 600 

SiQ@ IF W$>“"7" AND Wc" se" THEN 
30QTQ 370 

520 REM BINARY OPERATOR 

S30 IF 5:2 THEN GOTO 9990 


justify the learning experience. a” 


SEA WAR 
FOR ZX81 


This game is designed for one or two players. Each player has three submarines. As a certain 
number of points are reached, bonus submarines will be given. When the game is going on, the 
higher the score you get, the more that hostile features will appear on the screen. 


The features which appear on the screen are as follows: 


Submarine, Warship, U-boat and Helicopter. 
Submarine 


This feature is under your own control and is loaded at the left hand side of the screen. The keys 
‘9' and ‘0’ are the firing buttons for the upward missiles and forward missiles respectively. 


The submarine can be moved in four directions; it can move upwards and downwards by 
pressing keys ‘7’ and ‘6’ respectively. In order to move forward, you press key ‘8 and it will draw 
back to its previous position when you release the button. Also, the submarine can be moved 
diagonally upwards or downwards by pressing both keys ‘8’ and '7’ or keys ‘8 and ‘6’ respective- 


ly at the same time. 


=4@ LET S$=S-1 
550 LET S(5)=VAL ("S(S) “+UsES ( U-boat 
Oe certs This is the hostile submarine: It drifts under the sea level randomly, from right to left. Missiles are 


: RN 
S63 REM UNARY OPERATOR 
: tWEee'S (57 "3 


S=S4+2 
S519 LET £5153 =VAL WS 


SASIC SUBROUTINE 


142393 REM STOP . 
1500 STOP 

1501 RETURN 
15395 IF 5:2 THEN GOTO 9998 
i506 PRINT Si53 


CES ooa 


fired as it approaches your submarine. Destroying a U-boat scores 20 points. 


Warship 


This is the enemy destroyer which will release bombs diagonally as it drifts on the sea surface 


from right to left. 


The destruction of a warship is done by either firing a vertical missile or, when the submarine is 
just under sea level, by pressing keys ‘7’ and ‘0’ which release a horizontal missile. Otherwise the 
missiles will just pass under the ship bottom. Each destruction of this feature scores 50 points. 


Helicopter 


As you reach a certain score, helicopters appear on the left hand corner of the screen, they drop 


tote seine. T vertical bombs as they hover above the submarine. To destroy the helicopters, vertical missiles 
peas ELS ie can be fired by pressing key ‘9’. Each helicopter destroyed scores 100 points. 

4525 PRINT “COMMANDS” *New Game—ADDER—Arcade-type game. 

4526 FOR I=i TG D 


S25 NEXT I 


Shoot the numbers as they pass across the screen, but watch your total. 
Each game $9.95 plus $2.00 postage/handling 


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1530 TE S30 THEN PRINT S15) Distributor Inquiries Welcome 
1531 RETURN 

289 REM ERROR DETECTED 

S298 PRINT “7? “JUS 

22333 RETURN 


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Software, 


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Computer make & model Disk?(y/n) 


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The 
Unprintable 


Characters 
Michael W. Schultz 


The purpose of this article is to illustrate the 
power of the CHR$ function. The argument 
for the CHR$ function is a numeric value code 
from 0 to 255. This is the entire character set 
of single letter characters, keywords, and to- 
kens. Refer at this point to the character set 
listing in the appendix of your programming 
manual. You will see that character codes 
67-111, 122-125, and 195 are not used in the 
ZX81 system. You can verify this by running 
the program in Figure 1. The unused codes are 
shown as question marks. 


Figure 1. Ni Ne SD ea 
1a FOR W=8 FAQ 255 
28 PRINT CHRS WN; 
3@ NEXT N 


Now change line 10 to 10 FOR N= 128 to 
191 and hit RUN then ENTER. The characters 
displayed cannot be entered from the 
keyboard itself. The interesting thing about 
this concept is that graphic strings are printed 
very rapidly and this may be applied to any 
work dealing with high speed graphics. 

The CHR$ function can also be used to 
compare other nonprintable functions such as 
the cursor operation symbols like “æ >”; 
“œ”; “4”; “p”; which cannot be placed onto 
the screen. This is accomplished by applying 
a string equivalent, which can be called by 
using their respective CHR$ codes (112-115). 
We can examine an example of that code by 
using the CHR$ (114) for the backspace cur- 
sor in Figure 2. Type in Figure 2 at this point. 


Figure 2. 


18 LET AG=INKEYS 
2@ IF AS="" THEN GaTo ia 
3a IF AS< >- CHRS 244 THEN GOTO 7 


4@ SCROLL 

S@ PRINT “LEFT CURSOR 0N” 
5a GOTa ia 

78 SCROLL 

SQ PRINT AS 

9@ Gara 12 


In the SLOW mode hit RUN then ENTER. 
What happens when you depress SHIFT then 
hit 5? Try the other SHIFTed cursor positions. 
Experiment with ENTER and other keyboard 
letters, numbers, and tokens. Hit BREAK to 
STOP the program when you are finished. "a 


Michael W. Schultz, 3650 Mossvale Dr., Mobile, 
AL 36608. 


SYNC Magazine 


TS1000-ZX81 


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B Please send_—_ copies of KRAKIT” Please print: - 
Bat $19.95 plus $1.50 shipping. : 
E Total enclosed is L] check Name 8 
5 money order Be š 

r 
- Charge to LJ visa L] Mastercard sags F | 
i a Sees las ene Poe Aca eee ae Pesce City State ¥ 
g Expiry Signature a =o 4p - 
4 Allow 2 weeks for personal checks. g 


Qu EEE BE BBE EB BRE SB BBS BESET ees LLL LLL La 


Dealer inquiries welcome. 


other FINE 
PRODUCTS 
from 


INTERNATIONAL 
PUBLISHING Y 


3952 Chesswood Drive 
Downsview, Ontario, Canada M3J 2W6 


e GAMES « GAMES e GAMES ° 


MARINE RESCUE: fast action underwater 

| TANK TRAP: destroy enemy planes & lanc 
mines 

GALAXY INVADERS: repel fleets of invaders 

INVADERS: the classic computer game 

ZX SCRAMBLE: a fast-moving space game 

CROWN & SCEPTER: a medieval adventure 

GALACTIC COMMANDO: a space war 

adventure 

TRACK DOWN: an adventure in the old west 

BLACKJACK: as played in Vegas 

SLOTS: beat the one-armed bandits 

ZX CHESS |: 6 levels: black or white: save 
games 

ZX CHESS II: chess master: 7 levels: champion 
rated 

1K CHESS: 1 level: no castling or en-passant 

PLANET OF FEAR: find your stolen spaceship 

INCA CURSE: get gold out of the temple 

SHIP OF DEATH: free your ship from an alien 

cruiser 
NANTIR RAIDERS: arcade game: 4 waves of 
attackers 

famous arcade game: chase 

ghosts in a maze 

1K GAMES: 11 games for unexpanded 

ZX81/TS1000 
SHOOT OUT: how fast are you ‘‘on the draw’ 


GOBBLE MAN: 


FAMILY EDUCATION & HEALTH 
& ENTERTAINMENT 


WEIGHT CONTROL: a personalized weight 
loss program* 

CONSTELLATION: your computer is your 
telescope* 

SOLAR SYSTEM FILE: a databank on the 

solar system* 
BIORHYTHMS: plot your physical, emotional, 
intellectual cycles” 
BOOK OF DAYS: facts, trivia, birthdays in a 
datafile * 

PERSONAL RECORDS 

STORAGE SYSTEM: create a personal 

datafile * 

FLASHCARD: memory aid, learning aid, testing 

device 
MOVIE HANGMAN: guess the movie; beat the 


Hangman 


PROGRAMMING AIDS 


Z-AID 1.0: a machine code programming aid 
ZX BUG: for debugging, editing & running 
machine codes 
ZX ASSEMBLER: powerful tool for machine 
code programs 

TOOLKIT: add 9 commands to basic; including 
renumber 

ZX FORTH: ease of basic with machine code 

speed* 


* comes complete with a detailed guide 


DEALER ENQUIRIES INVITED. 


8K ROM 
1K RAM 


Programming the LOAD Command 


Michael J. Gentilcore 


Do you have some machine code programs 
stored on tape that require POKEing RAM- 
TOP before LOADing the program from cas- 
sette? Or are you writing your Basic programs 
around a favorite machine code POKEing 
routine? If so, knowing how to program the 
LOAD command can be a real convenience. 

Using the LOAD command in a program 
allows you to read and execute a series of 
programs on tape without the hassle of start- 
ing and stopping the cassette deck. The first 
program can change RAMTOP in preparation 
for a machine code POKEing program. The 
next program(s) can POKE in your USR 
routine(s) above RAMTOP. The last program 
can be a basic program that uses the USR 
routines. 

To illustrate how this works in practice, the 
LSCROLL program written by Douglas D. 
Sharp will be used (SYNC 2:2). 

Listing 1 is a program to change RAMTOP. 
Type in this program. To store this program on 


Michael J. Gentilcore, 503 Cannonbury, Webster 


_ Groves, MO 63119. 


Listing 1. RAMTOP Change. 


1@ POKE 16386S,686 
20 POKE 16389,127 
30a LORD “LSCROLL” 


“TEST LScCROLL” 
Sa Gara ig 


tape, you need to be able to distinguish be- 
tween the LOAD and SAVE modes by looking 
at the TV display. If you are unfamiliar with 
the LOAD pattern, type RUN and ENTER to 
observe the LOAD pattern. Hit the BREAK 
key to exit the LOAD mode. When you know 
what the LOAD pattern looks like, you are 
ready to store this program on tape. Use the 
following procedure: 

1) Press CLEAR and ENTER, RUN 500 
and ENTER, and start your cassette deck in 
record mode. 

2) Observe the SAVE pattern on the TV 
display. 


Listing 2. LSCROLL. 


4 LET C=0 
5 REM ALL OS IN THIS LISTING 
6 REM ARE ZEROS. 

10 LET D$="3AEE7FFEl6DA517F3E0 
032EE7F3AEF7FD600CA617FFE15D2617 
FC3667F3E1632EF7FF53AEF7F47F13AE 
E7F80FE16DA857F26002E163AEE7F4FO 
600ED427D32EF7FED5BOC400EFFF5 3AE 
E/7F6FF1260006001LAFE76CA9F7F13C39 
5 7FOCA7E5ED42E1CAAC7F13C3957FO60 
OF 5 3AEF7F4FF1C5D5E1237EFE76C2B77 
FESA7ED522B7D4DD600E1C2DO7FE5D1C 
3E57F3DC2D87F13C3E17FO6000B13D5E 
123EDBO3E001213C10B79D600C2B47FC 
90000" 

20 FOR X=2 TO 344 STEP 2 

30 LET P=(CODE D$(X-1)-28) *16 

40 LET P=P+CODE DS$(X)-28 

90 POKE 32579+INT (X/2),P 

60 LET C=C+P 

70 NEXT X 

80 PRINT C 


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3) Stop the cassette deck when the LOAD 
pattern appears. 

4) Hit the BREAK key to exit the LOAD 
mode. 


Listing 2 is the program for LSCROLL. 
Some readers will already have it on tape. For 
those who do not, carefully type in the pro- 
gram and RUN it. If, within a few seconds, 
the number 22093 appears on your screen, 
you have correctly entered the program. 

Modify the LSCROLL program by typing 
in the additional statements in Listing 3. 
SAVE the program on tape directly after the 
first program. Use the same procedure as be- 
fore—except substitute the command RUN 
100 for RUN 50. 

Did you notice the screen go blank before 
the LOAD pattern appeared? The program 
was executing during this time. 

Type NEW and ENTER to erase the 
LSCROLL listing. 


Now type in the program in Listing 4. Save 
this program after the second program. Use 
the command 

SAVE “TEST LSCROLL” and ENTER 
This program is being SAVEd in the standard 
fashion under the name “TEST LSCROLL”. 

Now it is time for the acid test. Rewind your 
cassette deck into position to LOAD the first 
program. You should be able to LOAD and 
execute all three programs in a single loading. 
Let’s go: 

1) Type LOAD “TEST LSCROLL” and 
ENTER. 

2) Start the cassette deck. 

3) Observe your TV display. 


Listing 3. Additional Statements. 
5a LOAD “TEST LECROLL" 


9a STOP 
100 SAVE “LSCROLL" 
1128 GOTO 4 


SEEE E E EE ee 


Listing 4. Test LSCROLL. 


10 PRINT AT @,13; "TEST"; AT 5,1 
3: "HELLO"; AT 20,13; "GOODBYE" 

20 POKE 327950.2 

70 POKE 32751.20 

40 PAUSE 20 

5@ RAND USR 32583Üü 

59 GOTO 4a 


At Last Your Chance To 
Lexel The Machine Code 


TIMEX 1000 AND ZX81 OWNERS 


% Ifyou are interested in finding out how a computer really works 
and want to experience true programming power — the machine 


Code Test Tool is the answer. 


program as standard. 


x% The Machine Code Test Tool is a utility program which comes 
complete with tutorial course enabling you to enter, test, display 
and debug hexadecimal machine codes simply and quickly. 


x The Machine Code Test Tool is constructed to help the absolute 
beginner who wishes to explore this fascinating subject, or the 
expert keen to polish up his machine code programs. 


x A HEX: decimal conversion routine is contained within the 


You should be able to distinguish the follow- 
ing phrases: 

a) LOAD pattern. 

b) Read pattern for the first program. 

c) LOAD pattern. 

d) Read pattern for the second program. 

e) Execution of the second program (blank 
screen). 

f) LOAD pattern. 

g) Read pattern for the last program. 
Continuing with the sequence, 

4) Screen returns 

5) Stop cassette deck 

6) Type RUN and ENTER 

Super! A single LOADing has changed 
RAMTOP, POKEd in a USR routine, and 
read in your Basic program. Only the program 
of interest is stored in memory. It is almost as 
good as buying a ROM that has your favorite 
USR routines on it. 

A couple of questions for the reader to en- 
joy: 

1) How could you modify the last program 
so that it runs itself after loading? 

2) What do you think would happen if the 
BREAK key is pressed during the LOAD 
cycle during the phases that are asterisked? 


"a 


E a oe a a a a Dd eee 
Post to: R. L. ASSOCIATES, 614 W. Manchester Bivd., Inglewood, Cal. 90301 


z Please rush................Z2X81.M.C.T.T. at $19.95 ($25.95 Canada) 
H Send payment to above address 


s aay ee ee ae 


Do m m ee es es 


GLADSTONE- "ELECTRONICS 


Cassette Software 


ZX FORTH 


Simplicity of BASIC with the 
Speed of Machine Code 


A complete implementation of the FORTH language for 
the ZX81 and TS1000 computer. 
FORTH’s most distinctive feature is its flexibility. The 
basic unit is the word — the programmer uses existing 
words to define his own which can then be used in fur- 
ther definitions. FORTH is a compiled language so pro- 
grams run very fast (typically five times faster than 
BASIC). 
ZX-FORTH is supplied on cassette and is accompanied 
by extensive documentation: 

56-page Users Manual 

8-page Editor Manual 


Artic 


ZX BUG 


Machine Code Monitor and Disassembler 


ZXBUG is a powerful tool for machine language pro- 
gramming. It is 4K long and uses memory from 71EO to 
the top memory. ZX BUG works in hexa- 
decimal (base 16), not decimal, so all addresses are a 
maximum of 4 Hex bits long. Provides a total of 28 com- 


mands. 
Artic $14.95 


ZX 
ASSEMBLER 


This Machine Code program occupies 7K of memory 
and locates itself at the top of memory. The program isa 
full Editor/Assembler and Monitor. Labels may be used 
instead of any string. The features include Line Inser- 
tion/Delete, Insert Characters, Auto Repeat on all keys. 
The monitor has facilities to inspect memory, registers 
and run machine code programs. 

$14.95 


Artic 


TOOLKIT 


9 Powerful New Functions! 


RENUMBER. This routine renumbers a program in any 
step and from any line up to 9999 

DELETE. This command deletes a group of lines in a pro- 
gram. 

MEMORY. Prints how much spare memory is available. 
DUMP. Displays current values of string and numerical 
values, except arrays. 

FIND. Will find any String of up to 255 characters and list 
each line containing that string. 

REPLACE. Replaces any string of up to 255 characters 
by any other string. 

SAVE. Transfers program in computer to below RAM- 
TOP. 

APPEND. Allows two programs to be joined. 

REMKILL. Removes all REM statements froma program, 
otherwise leaving it unchanged, preserving memory. 


Artic $14.95 


GLaDSTon 


Mail order to 1585 Kenmore Ave. 


° GLADSTONE-'-ELECTRONICS 


$29.95 


GLADSTONE-' ELECTRONICS 


GLADSTONE ELECTRONICS 


GLADSTONE -ELECTRONICS 


GLADSTONE- '-ELECTRONICS 


GLADSTONE- ELECTRONICS 


Get serious about Zx8i 
& TS 1000 Computing 


DATA STORAGE SYSTEM 


For 16K or greater ZX81 


PRICE INCLUDES: 


1. PROGRAM TAPE 

2. 8-PAGE BOOKLET 

3. THREE DATA STORAGE 
TAPES 

4. STORAGE CASE 


$34.95 


MULTIFILSB PLUS 


e 
PROGRAN tS 2 BUS -E- TE 


SET UP FILE PARAMETERS 
CREATE FILE 
DIFY PF 


R 
SAVE FILES ON TAPE 


GNANA UN 


ENTER YOUR CHOICE !1-9Ə) 


Data Storage System 


An amazingly versatile multi-purpose filing system for 
the 16K ZX81. The program is menu-driven, and number, 
size and headings of files are user-definable. Both string 
and numerical files are catered for. Files may be 
created, modified, replaced, and searched, and are pro- 
tected by an ingenious foolproof security system. Out- 
put to the ZX printer is also provided. The program 
comes on cassette, together with three quality data 
cassettes for file storage, and comprehensive documen- 
tation, describing a host of applications for both 
business and personal use. Supplied in an attractive 
storage case. If your ZX81 is bored with playing games, 
then this program will give it plenty to think about! 


The Complete ZX81 
and TS1000 Library! 


OLS 8 e Ome ata oe ae. 65a 6 a, é 6-616 oe 16-6 ove: a 


49 Exploding Games for the ZX81 .............. 10.95 
Not Only 30 Programs for ZX81:1K ............ 14.95 
Machine Language Made Simple for Sinclair .... 
Mastering Machine Code on your ZX81 ......... 12.95 
ZX81 Rom Disassembly: Part A ................ 14.95 
ZX81 Rom Disassembly: PartB ................ 
Understanding your ZX81 ROM ................ 


CALL OR WRITE FOR FREE CATALOG 


LECTRONICS 


Buffalo N.Y. 14217 Checks or money orders. 


with Quality Hardware and Software 
from Gladstone Electronics 


ZX81 Professional Keyboard 
and Case 


A full-sized professional keyboard for the ZX81 Features 
47 keys and a full-sized space bar. Connects to the ZX81 
with no soldering required, via a plug-in flexible connec- 
tor. You can purchase the keyboard only, or the optional 
metal case that holds both keyboard and ZX81. Expan- 
sion devices (i.e. RAM packs, etc) connect to the ZX81 
edge-connector which extends from the rear of the 
cabinet. 

A professional keyboard makes program entry easier 
and less error-prone. 


Keyboard (KB-1) ............... $85.00 
Metal case for keyboard 
and ZX81(MC-1) ............... $25.00 


ia an E ONAA NA Aa: i 

TEELE 8 6 oo rr x 
PRS A 
ites ee 
re: 


with “piggy-back’’ feature 


A sensible choice for 16K RAM owners. Jigsaw 32K RAM 
‘piggy-backs’ onto your 16K RAM to give a total memory 
of 48K! If you do not own a 16K RAM, you may use a 32K 
RAM instead. At a later date you may add the ZX81, 
TS1000, or Jigsaw 16K RAM, should you decide you re- 
quire more memory. 

A very useful, unique Jigsaw memory feature is the pilot 
light showing if your ZX81 computer/memory is 
powered. 

Larger memory enables longer programs and greater 
data bases, enhancing the value of your personal com- 
puter. And the Jigsaw 32K is part of a fully compatible 
ZX81 and TS1000 system of add-on products, Additional 
exciting Jigsaw products to follow shortly! 


BERK RAM: 49.95 


Expands the ZX81’s memory Capacity to its maximum. 
Use instead of 16K RAM. Same features as other Jigsaw 
memory products including pilot light and full com- 
patibility with other upcoming Jigsaw products. 


16K Ra $49.95 


Equivalent to ZX81 or TS1000 16K RAM. Fully compati- 
ble in appearance and performance with other Jigsaw 
products. 


Call (716) 874-5510 


For Visa, MC Orders 
No CODs. Add shipping 


Introducing 


KRAKIT 


WIN $20,000 or MORE 


The Ultimate 
Adventure 


‘MY SON,by the time you receive this package, I will be 
dead. This is my legacy to you. All my life | have worked 
hard to make a living and save money for your future. AS 
you know I was an international courier. Contained on 
this cassette are 12 clues of an international flavor, 
which will furnish you with the information to gain ac- 
cess to a bank account. In that bank account is a 
minimum sum of 10,000 pounds sterling, which I have 
accumulated on your behalf over the years. The longer 
the sum remains in the account the greater the amount 
will become. | could have bequeathed the money to you, 
but I feel it is in your interest to solve these clues. Then | 
will feel you are mature enough an adult to handle this 
legacy. 
God bless you always, your loving father. . . 

So begins KRAKIT, the ultimate adventure and treasure 
hunt on the ZX81. The bank account and the prize actual- 
ly exist. Crack the puzzle and the prize is yours! Krakit 
consists of 12 clues. In each clue there is a reference to 
a country, a city or town and a number. When you have 
solved the first clue, you will need to enter the two 
words and the number to release the next clue. It is 
necessary to solve all the clues to find the correct 
answer. If you do you will be supplied with two airplane 
tickets. When you arrive, a check for a minimum amount 
of 10,000 pounds sterling will be presented to you. Fur- 
thermore for every copy of Krakit sold a further dollar 
will be placed in the bank account. 

Here is the type of clue you will find in Krakit: 
‘Where it all began. Where the torch was first lit. Where 
muscles and sinews strain. Where our heros won ac- 
claim. 

Where the symbols hold the key.’ 


KRAKIT.16K RAM $19.95 


RULES. 1. The first person to be confirmed by the judges. 
to have completed all the clues correctly will be the win- 
ner. 2. There will be one winner only. 3. No person 
related to |.P.S. is eligible. 4. Offer not valid where pro- 
hibited by law. 

*Trademark of International Publishing & Software, Inc. 


MAZOGS 


MAZE ei E a — r 
ADVENTURE 


$9.95 


A new standard in ZX81 programming. MAZOGS 
presents the best use of ZX81 graphics to date Written 
in machine code, MAZOGS is fast, exciting, and 
challenging! 

You are confronted by a large complex maze which con- 
tains a fabulous Treasure. Within the maze are the 
Mazogs who will involve you in combat when you meet 
them. Each game begins when you meet them. Each 
game begins with a different randomly created maze. 
You will not see all of the maze. As you move through 
the halls, you will be startled by the qualıty of the 
graphics animation and the speed with which the game 
progresses. 

Once you have mastered the first two levels of the game, 
you are ready to challenge the Maniac Mobile Mazogs 
who move about in a totally unpredictable manner. 

To those who say the ZX81 is not a good games-player: 
we suggest you try your luck with Mazogs! (16K or 
greater) 


Have fun with ZX8i 
& TS 1000 Computing 


GALAXY 


INVADERS 


$14.95 


An excellent version of the classic space game. Protect 
your seven lives against fleets of hostile invaders, who 
swoop down and attack quickly. This version is an ex- 
cellent demonstration of the capabilities of the ZX81 or 
TS1000 to entertain and excite for hours. 


ZX 
SCRAMBLE 
$14.95 


Pilot your space craft through a fast moving, complex 
space maze. Watch out for missiles being fired from all 
directions. You can shoot back or evade them. Written in 
machine code for fast-paced excitement. 


MARINE 
RESCUE 


$11.95 


Your ZX81 becomes the command console as a diver 
descends to the sunken submarine Nautilus to rescue 
as many of the stranded crew as possible. Its a race 
against time as your oxygen supply must be replenish- 
ed. It’s also a constant battle against marauding sharks 
which you can attempt to blast with your laser. 


GLaDsTon 


CHARGE TO: 
§Livisa [] MASTERCARD 


i account number 


Sıgnature 


Date 
f NAME 
i ADDRESS 


7 CITY: STATE: 


Call (716) 874-5510 for Visa, MC Orders 


Pee a a ee a a oe ‘U 


Please rush me: 


Now Choose 
from 3 great 
games! 


ZX CHESS... 


Full graphic display of chess board. Six levels of play, 
two of which play within competitive time limits. You 
choose black or white. Plays all legal moves including 
castling and en-passant. You can save games in pro- 
gress on cassette. Displays moves of game on screen, 
or output yo printer, for analysis. Board can be set up in 
any position, you can even change sides mid-game. 
Clear entire board with one command: for end game 
analysis. Written totally in machine code, ZX CHESS 
(Enhanced) is a superb game for the advanced chess 


player. 
16K $12.95 


ZX CHESS II (CHESS MASTER) 


The strongest chess game available on ZX81. ZXCHESS 
ll has not ben beaten. All the features of ZX CHESS 
(Enhanced), plus much more. Has a book of 32 opening 
moves. Can play at 7 levels, four of which play within 
competition time limits. A move is suggested by the 
ZX81 if requested. 

$24.95 


16K. 


1K ZX CHESS 


A good introduction to chess for 1K ZX81/TS1000 
owners. Even within this limited memory space, a full 
graphic representation of the chess board is included. 
Single level of play. Does not accept castling or en- 
passant moves. 


BLACKJACK 
$14.95 


Blackjack at its best. Blackjack as it played in the 
casinos of Nevada. Up to five players can play against a 
dealer with a fifty-two card deck. Split pairs, double 
down, and even buy insurance. The deck is reshuffled 


only when needed — allows for a continuous game. 
Your winnings and losings are displayed after each 
hand. 

Adventure Games! 

Galactic Commando... .3 22 1.05 i se 8 11.95 
COW SCOPO 6 Seat nese Pads ae E a 11.95 
"RMN DOU Doig sg pa ah spk a a E T 11.95 
BiG WO -r A Gr en Es eg ©. ee ee 14.95 


LECTRONICGS 


tax 
SHIPPING 
ZIP: TOTAL > 


To: Gladstone Electronics, 1585 Kenmore Ave., Buffalo N.Y. 14217 


$12.95 | 


ORDER FORM 


p 

Į 

$ 

New York : 
Res. add oe f 
et 

i 

d 


Call or write for free TS1000 & ZX81 catalog 


È 
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$21U0819317-,-3u01Sde819 s21u0u19317.,Ju01Sade19 SJIUO0Y19717}. -3U0L1S0819 


SJIlU0Y1L1IJ1} -JU0LS0QE19 


PUT YOUR TIMEX/SINCLAIR 
_ COMPUTER TO WORK! 


TIMEX/SINCLAIR SOURCEBOOK™ 
e SOFTWARE 
e HARDWARE ADD-ONS 
e BOOKS/CATALOGS 


Maximize your ZX80, ZX81 or 1TS1000 
computer investment with the TIMEX/SIN- 
CLAIR SOURCEBOOK which lists programs, 
hardware accessories and reference books. 
-The SOURCEBOOK allows you to quickly 
identify the ZX computer products you need 
from a wide variety of sources to put your com- 
puter to work. Order your copy today — 
only $6.95 
TIMEX/SINCLAIR SOURCEBOOK™ 

Micro Design Concepts 

Dept. SC-1 

P.0.Box280 

Carrollton, TX 75006 

Please send me the TIMEX/SINCLAIR 

SOURCEBOOK. | enclose $6.95 plus $1.25 

P&H ($2.50 outside the U.S.) Add sales tax 

in Texas. 

Name 

Address 

City 

ol Taal acta 2 SO ag ea, ie eT a ee SN 
Have a product you would like listed? 

C Check for an application for free listings. 


CHANGE YOUR 
TS1000/ZX81 TO COLOUR 


. with 
KOLORWORKS 


* Plugs into ZX81/1000 (edge connection) 
* All text will run on the color t.v. 

* Module contains its own memory 

* Pixel resolution up to 256x196 

* Extended color basic: 


for $149.95 
Color game cassette for $9.95 


EARLYBIRD SPECIAL 
—with orders placed between Jan. 1 
& Jan. 31 receive the game 
cassette ABSOLUTELY FREE 


Shipping & handling $4.95 
SEND CHECK OR MONEY ORDER TO: 


BRAINCHILD COMPUTER WORKS, INC. 
P.O. BOX 506 
PEWAUKEE, WI 53072 


For further information 
Send $2.00 (credited to order) 


WI Residents add sales tax 


Please allow six to eight weeks for processing. 
Thank you. 


WATCH FOR: 


GAAMWORKS 
Joystick ports / Sound / Cartridge slot 


54 


TIMEX-SINCLAIR 


1983 Directory 


* Where to find: Disk Drives, RAM Extensions, 
Printers, Modems, Key Boards, Game and Serious 
Software, Books, Programming Aids, and Other 
Exciting Accessories! 

* Articles on: Timex Sinclair 1000, History & De- 
velopment, New Accessories, How-To-Projects. 

* Reviews of: Books & Monthly Publications 


No ZX81 or Timex 1000 owner should be without 
this valuable resource book! 


Only $5.00 ... postpaid 


How to order: Make checks and money orders in 
the amount of $5.00 payable to E. Arthur Brown 
Company. MN residents add 5% sales tax VISA & 
Mastercard: Give card name, number, expiration 
date, and sign your order. Finally, print or type your 
name, address, and zip code on a blank sheet of 
paper and send it, along with your method of pay- 
ment, to the address below. 


E. Arthur Brown Company 
Department ZX-3 

1702 Oak Knoll Drive 

Alexandria, MN 56308 


ANGLO-SOUTHERN 
SOFTWARE 


presents 
AN UNBELIEVABLE BARGAIN!! 


TWO GREAT PROGRAMS FOR THE ZX81 (16K) 
ae ONE CASSETTE....FOR THE PRICE OF 
NE! 


SIDE A “STARCOMMAND’” 


Superior version using machine code to trans- 
port you to the bridge of starship Thunderer. 
Klingons-sensors-shields-phasers-photon torpedos 
warp drive-starbases-real time. . . . but are you up to 
the command? 


SIDE B “MASTERCHESS” 


Fast machine code program-six levels of 
play-play-black or white-recognises’ castling’ and ’en 
passant’-set up board feature. Level one will probably 
surprise you! 
BOTH PROGRAMS ON ONE 
CASSETTE FOR ONLY.... 


$9.95 
(including P&P) 


Send $ cheque or sterling money order avail- 
able from your bank to: 

ANGLO-SOUTHERN SOFTWARE, 

12 Roseberry Avenue, (Dept 6), 

Eastbourne, East Sussex, England. 


1982 TAX RETURN HELPER 


A set of 7 ZX81/TIMEX programs (16K 
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The programs perform all computations 
and even detect some of your errors. Like 
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are updated on the spot. The forms can 
be printed and/or saved on tape for future 
use. Form 1040 and Schedules A, B, C, 
C1/C2, D and E are featured. 


The 1982 edition will be available in Jan- 
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instructions) - is tax deductible. (Only $7 
for the buyers of the 1981 edition.) 


From: KSOFT, 845 Wellner Rd., Naper- 
ville, IL 60540 


A Fingers (& 
Jack Ryan : 


N 


Occasionally a program has lines which are 
almost identical usually because of condi- 
tional statements. For example: 


a20 IF A$ ió TO 14)="NOTAFRAID" 
THEN FRINT "GH OH "; Nfi 

F0 IF A$(6& TO 14)="NOTAFRAID" 
THEN FRINT "YOU FORGOT A SFACE 4A 
TER NOT" 

S40 IF AS$(6& TO 14)="NOTAFRAID" 
THEN FRINT "TRY IT AGAIN" 

ooO IF AS(6& TO 14)="NOTAFRAID" 
THEN GOTO 250 
Cir s 

260 IF AS$(6 TO 14)<>"NOQTAFRATD" 
AND A$ "I AM NOT AFRAID OF COM 
PUTERS” THEN: PRINT "SOMETHING TS 
H. Bẹ: "WRONG. TRY IT AGAIN" 

370 IF AS$(G& TO 14)4£>"NOTAFRAID" 
AND At "I AM NOT AFRAID OF COM 
PUTERS” THEN GOTO 250 

(R$ is either a space or the 
word. “STIL”. 


Such lines quickly become a pain to the 
fingertips, but there is an easy way to avoid 
these agonies by using the EDIT function. 

When you have typed and ENTERed the 
first line of the series with similar lines, hit 
EDIT and the line will be brought back to the 
bottom of the screen. Change the line number 
to the next line number needed and move the 
cursor to the end of the line. Then, using DE- 
LETE, remove everything that is not needed 
for that line. 

Now add the new material and ENTER the 
line. Repeat the process for as many lines as 
needed using the EDIT key to bring down the 
line that is closest in content to the next line 
you want to type in. You may even want to 
plan your program so that you can take advan- 
tage of this technique from the beginning. 

The procedure saves time and avoids the 
tedium of entering the same thing over and 


over and... = 


Jack Ryan, Rt. 5, Box 244, El Dorado, AR 71730. 


SYNC Magazine 


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There is a precept in the Buddhist 
philosophy which states that for a person 
to truly understand any thing, the person 
must merge with that thing and become 
one with it. I have not reached the state 
where I can merge with anything, let 
alone an abstract concept such as “ran- 
domness,” but I was reminded of this 
precept when I tried to apply the RND 
function to a program that I was develop- 
ing. 

The program was in the form of a quiz 
game, and I wanted to use the RND 
function to select the questions. I had 
chosen to go this way so that the questions 
would not appear in sequence. This would 
prevent the player from memorizing the 
answers in sequence. Never knowing 
which question would be coming up next, 
the player would have to think in terms of 
relating the answer to the question. He 
would not be able to respond in the man- 
ner: The answer to question number 5 is 
apples; the answer to question number 6 
is beans, etc. 

I was using a random statement in the 
form: 

10 LET A=INT(RND*10)+1 
which allowed me to select randomly 
from a set of ten questions. 

This seemed to work well with one 
exception. Every so often, the same ques- 
tion would immediately repeat. So I 
pressed a friend into service as an objec- 
tive player to help me debug the program. 
After the same question had repeated 
several times in a row, he turned to me 
with a raised eyebrow and asked, dryly, 
“What’s the matter—is it broken?” 

I realized that I had a situation that 
could cause some embarrassment, so I 
decided to dig deeper into the RND func- 
tion to see if there was anything that 
could be done to solve the problem. 


The RND Function 

Obviously the starting point was to get 
out the ZX81 handbook and look up the 
RND function. 


Ronald W. Duguid, 4352 Grow Road, NW, 
Stanton, MI 48888. 


56 


Then I began to experiment with the 
RND function by using the program: 

10 FOR C=1 TO 10 

20 LET A=INT(RND*10)+1 

30 PRINT C;“.#”";A 

40 NEXT C 

50 STOP 

This program selects a number between 
1 and 10 and prints it. Several test runs 
are shown below (read down): 


i GNET 
ys DTT 2 
S: p Aa ee 
4. PARE e 
D3 PAA ERS 
6. 1 4 4 
7 10 10 5 
8. e Be Mee. 
9, 2! $0 
10. 4 3 2 


This was definitely not what I wanted. 

The handbook says that the RND func- 
tion is not truly random, but is pseudo- 
random, being based on a fixed sequence 
of 65536 numbers. The RND function has 
a control called RAND which, when fol- 
lowed by a number other than 0, will 
cause the RND function to start at the 
same point each time the RND statement 
is executed. If RAND is followed by 0 (or 
no number, at all), then the RND function 
is controlled by a variable called 
FRAMES. 

An initial control number, which is 
another variable appropriately called 
SEED, is used to generate the RND num- 
ber. SEED is controlled by both RAND 
and FRAMES. So the next step was to dig 
deeper by examining FRAMES, SEED, 
and RAND. 


FRAMES 

FRAMES acts like a 16 bit down 
counter which is located at addresses 
16436 and 16437. Address 16436 contains 
the LSB (least significant byte) of the 
count number, and address 16437 con- 
tains the MSB (most significant byte) of 
the count number. 

The count begins at 65536 and counts 
down to 0. When it reaches 0, it resets to 
65536 and starts to count back to 0 again. 


FRAMES can be PEEKed by using the 
program in Listing 1. It will sample the 
FRAMES counter (both bytes), and then 
print out the value. SAVE this program. 
It can be used later in the article. 

Each time you run this program, you 
will get a different series of numbers 
because the FRAMES counter is contin- 
uously counting. If you add the following 
statements: 

25 POKE 16437,0 

27 POKE 16436,0 
you will cause the FRAMES counter to 
reset to 0 at the start of every run, and 
the next number will always be 65531. 

The FRAMES counter is also used by 
PAUSE. When PAUSE is executed, bit 
15 of the FRAMES counter is set to 0 and 
the time of the pause is entered into the 
FRAMES counter. The FRAMES 
counter then counts down from this value 
to 0. FRAMES is clocked at the rate of 
approximately 60 counts per second, soa 
PAUSE 60 will cause the program to 
pause for approximately 1 second. With 
bit 15 being set to 0, the maximum count 
(2**15-1) for PAUSE is 32767. At 60 


Listing 1. RANDOM. 
10 REM “RANDOM” 


3@ FOR N=1 TO 20 
TE REN ACN) =PEEK 16435+2564 PE 


K 1643 
50 NE 
6@ FOR M=1 TO 20 
150 PRINT AT M,1:M a “IAM? 
166 XT M 


25 POKE 16437,0 
27 POKE 164936.0 


counts per second, this amounts to a little 
over 9 minutes at the maximum count. 
The pulse that causes FRAMES to decre- 
ment (count down) comes from the com- 
puter sync generator that controls the 
vertical sweep of the TV set that is being 
used as a video monitor. 


SEED 

SEED also acts like a 16 bit down 
counter. It occupies the two memory 
locations with addresses 16434 and 16435. 
Like FRAMES, the lower number address 
contains the LSB and the higher address 
contains the MSB of the count number. 
Since each memory location can hold 
only an 8 bit number, two locations are 
needed for the 16 bit numbers of 
FRAMES and SEED. 

SEED can also be PEEKed. Change 
Listing 1 as follows: 

LET A(N)=PEEK 16434+256*PEEK 
16435 
Add: 

45 RAND 0 

If the RAND statement is not added, 
SEED will not start decrementing. 

SEED does not act quite like FRAMES. 
The first count will be the last count 
recorded in any previous run. This seems 
to indicate that SEED is not counting 
continuously, but is switched on and off 
by the RAND statement. 


SYNC Magazine 


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49 EXPLOSIVE GAMES FOR THE ZX-81 
Edited by Tim Hartnell 


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—__— MAKING THE MOST OF YOUR ZX-81, by Tim Hartnell, (R4189-8), $16.95 
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SEED can be POKEd by using lines 25 
and 27 given above, as was done with 
FRAMES. The first count will be 0, but 
the next count begins with the current 
count in FRAMES. SEED does not start 
at 65531 after being POKEd to 0. 

Both SEED and FRAMES are SAVEd 
when you SAVE a program on tape. The 
numbers are re-enteered on LOAD, and 
the new count is started with these 
values. 


RAND 

RAND is used as a control for SEED. If 
RAND is given the value of 0, then SEED 
will take on the decrementing values of 
the FRAMES counter. If RAND is given 
any number from 1 to 95535, then SEED 
takes this value only. The output number 
from RND will always have the same 
value, no matter how many times it is 
run. You can test the effect of values of 
RAND other than 0 by using the same 
program that was used for SEED. Just 
change the value for RAND in line 45. 
For example: 45 RAND 100; 45 RAND 
250; etc. You will see that SEED will 
always have the RAND value in it. 


The Mersenne Prime 
As I continued to probe deeper into 
the subject of RND, I evenually came to 


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the information entitled,“For mathemati- 
cians only.” I read through this quickly, 
until I came to the statement, “65537 is a 
Mersenne prime, 2**16-1.” Wait a minute 
—not on my calculator! 

My curiosity aroused, I pursued this 
further and discovered that 65537 is not a 
Mersenne prime at all. It is instead a 
Fermat prime based on Pierre De 
Fermat’s equation: 


Be Ae 
Boel 


for n = 1, 2, 3...., (try n = 4). De Fermat 
and Mersenne, at the same time (early 
17th Century), were both trying to estab- 
lish a method of solving for prime num- 
bers. De Fermat’s effort (one of many in 
the field of mathematics) is expressed in 
the equation previously mentioned. 
Mersenne’s equation 


Mp = 2P-1 


(where p is any prime) has been found 
flawed, and is no longer considered valid. 

At that point, I prudently withdrew. 
Perhaps someone with greater mathemat- 
ical expertise than I will clear this matter 


up. 
The Revelation 


After looking through the explanations 
for RND and its accessory controls, I had 


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not found any way to solve my initial 
problem. Then, in a flash of insight (per- 
haps another Buddhist principle was at 
work here: “enlightenment”) I saw what I 
should have seen before: One of the pro- 
perties of “randomness” is that the same 
event can immediately repeat one or more 
times. 

This meant that there was no solution 
to my problem within the RND function. 


An External Solution 
Once I realized that I could not alter 
the RND function, I started looking for 


Listing 2. Inhibiting the RND Function. 


10 LET 5=8 

FOR C=1 TO 18 

3@ LET A=INT (RND#i@) +1 

40 IF A=B THEN GOTO 38 
ET B=A 


other ways to go. Listing 2 was the result. 

While this is no longer randomness, it 
does prevent the same number from 
immediately repeating. Lines 40 and 50 
now act to inhibit the RND function by 
not allowing the same number to repeat. 
If A equals B, then the program will go 
back to line 30 to get another number. It 
will keep doing so until A does not equal 
B. When this happens, A will pass through 
and B will change to equal the new value 
of A. 


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SYNC Magazine 


The Game 

Now all that remained was to adapt the 
game I had been developing with this 
method. “Space Crisis” in Listing 3 is the 
result. It uses the RND function in both 
the free and inhibited modes. 

The plot “Space Crisis” revolves around 
a spaceship that is returning from a mis- 
sion to a distant galaxy. The game starts 
with the spaceship in hyper-warp. ALEC, 
the on-board command computer, 
announces that the ship will leave hyper- 
warp and return to normal space. When 
the ship emerges into normal space (indi- 
cated by a star field appearing on the 
ship’s viewscreen), ALEC begins a routine 
announcement which includes the fact 
that he is taking back control of the ship. 
At this point, the crew begins to suspect 
that there is something wrong with ALEC. 
Their suspicions are confirmed as ALEC 
shows definite signs of trouble when his 
report breaks up. 

ALEC then begins a pseudo- 
conversation with one of his former pro- 
grammers, Professor Cypher, which 
resolves itself into a deadly game of ques- 
tions and answers on the Solar System as 
the ship hurtles toward certain destruction 
on Moonbase 2. The crew must rely on 
their own memories to answer ALEC’s 
questions because the ship’s library is 
locked up in ALEC’s memory banks and 
is no longer available to them. 


tired of space game RIPOFFS ? 


RAFICIAMES, 


When the ship enters normal space, it 
is traveling at a speed of 18000 mph. A 
safe speed for approach to docking at 
Moonbase 2 is 1000 mph, at which time 
the docking computer takes over from 
ALEC and docks the ship. Each time the 
crew answers a question correctly, ALEC 
reduces the ship’s speed by 1000 mph. A 
wrong answer does not reduce the speed. 
Each time a question is asked, the calcu- 
lated speed is reduced by 500 mph. (The 
calculated speed is the speed required for 
a safe docking at Moonbase 2.) 

If the calculated speed goes below 1000 
mph before the actual speed reaches 1000 
mph, the ship will crash. If the actual 
speed reaches 1000 mph before the cal- 
culated speed, the docking computer will 
take over from ALEC, and the ship can 
land safely. Only the crew’s knowledge of 
the Solar System can save them. 

The game begins when RUN is 
ENTERed. After a few seconds, a sim- 
ulated viewscreen and control panel will 
appear. The viewscreen is blank since the 
ship is in hyper-warp. ALEC’s announce- 
ment that the ship is leaving hyper-warp 
appears on the viewscreen. The entire 
screen will go blank for about 27 seconds 
(a long time for computer work, I'll 
agree). At the end of this period, a star 
field will appear on the ship’s viewscreen, 
indicating that the ship is now in normal 
space. A few seconds later, ALEC begins 


his routine announcement, and his mal- 
function appears. This is followed by his 
conversation with Professor Cypher, 
which is then followed by ALEC laying 
down the rules for the game. 

A prompt “L” should appear in the 
lower left-hand corner of the TV screen. 
This indicates that it is time for the player 
to enter the game. 

The game is played by the player read- 
ing the question appearing on the view- 
screen, and then ENTERing the name of 
a planet. (Misspelling the name of the 
planet is counted as a wrong answer.) 
When the ENTER key is pressed, the 
screen will display the player’s answer 
and the correct answer. At the same time, 
the computer will adjust the actual speed 
and the calculated speed to show the 
correct values. 

Win or lose, there will be an “end of 
game” message. After the message, the 
player will be asked if he would like to 
play again. If the answer is “Y”, the game 
will start with the questions; most of the 
graphics and all of the instructions are 
bypassed. If the answer is “N”, the pro- 
gram goes to 1999 which is the end. 


The Star Field 

I have used a random generator to 
generate the star field that appears on the 
ship’s viewscreen. The process could be 


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— — Listing 3. Space Crisis. 


10 REM "SPACE CRISIS" 9@ PRINT AT 7.2: “OUR SOLAR SYS 
12 REM BY. RONALD W. DUGUID ae YOU WILL" 
4352 GROW RD. NW 337 PAUSE 350 700 PRINT AT 6.2; “HAVE TO DO TH 
STANTON. MI 486885 338 FAST EM OVER 
13 REM OCTOBER 30. 1982 339 LET H=1 71a PRINT AT 10,2; "CAN THE CREW 
15 REN 2X81 2K ROMN/16K RAM 340 FOR G=1i TO 29 HELP ME? 
18 LET P=e 342 LET J=INT (RND#i@}+1 720 PRINT AT 12.2; "OF COURSE, T 
20 LET A=08 344 IF J=2 THEN GOTO 3508 HEY CAN. AND. IF" 
22 LET G=@e@ 346 IF J>=2 THEN GOTO 355 >30 PRINT AT 13.2: “THE ANSVERS 
24 LET H=8 350 PRINT AT H.G: “B" ARE CORRECT. you" 
26 LET J=8 252 GOTO SGO á 748 PRINT 4,2; "CAN CONTROL 
2S LET K=@ 355 PRINT AT H.G: `S THE SHIP." 
32 LET M=@ 560 IF G<=28 THEN GoTo 39@ 375@ PAUSE 10e@8 
34 LET N=@ 370 LET H=H+ti 760 GOSUB 2eee 
3S LET @=@ 375 IF H>=17 THEN GoTo 9392 770 PRINT AT 3,23; "YES, PROFESS@ 
#8 Ler Se=18000 age Sexe ge Reese Tee ft 
=. 3 ? PRINT AT 3.2; “CORRECT ANSVE 
44 LET GR=0 R06 LET Ce="BRIDGE"_ RoS WILL" ies 
165 CLS _388_PRINT AT 26.3; SA; TAB 6; “ZME 498 PRINT AT 4,2; “DECELERATE TH 
170 FAST H TRB 42; SC; TAB 27; “/MPH “; TAB E SPEED BY" 
175 FOR A=1 TO 60 23; C$ 88@ PRINT AT 5.2; “1000 MPH. THE 
180 PLOT A.4121 432 PAUSE Soe Y MUST REDUCE" 
1685 NEXT A 425 SLOW Se es 810 PRINT AT 6.2; “THE SHIP SPEE 
19@ FOR A=1 TO 60 410 PRINT AT 2.2; “ALEC HERE-WE Cc TO 1000 MPH" 
135 PLOT A.16 HAVE EMERGED" ae S20 PRINT AT 7.2; “BEFORE THE Cr 
200 N 226 PRINT AT 3.2; “FROM HYPER-LA i =ULATED SPEED" 
205 FOR A=1 TO 6&0 RE AND ARE" Sis 33@ PRINT AT 8.2; “REACHES 1900 
210 PLOT A.L4 43@ PRINT AT 4.2; "NOU MOVING A7 HEH. OR THEY" 
215 NEXT A Q SUB-LIGHT"™ 34@ PRINT AT 9.2; “WILL CRASH ON 
220 FOR A=1 TO 60 44@ PRINT AT 5.2: "SPEED OF 1800 MOONBASE 2." 
225 PLOT A.B @/MPH. WE RARE” £ 35@ PRINT AT 11,2: “QUESTIONS AR 
230 NEXT A- 45@ PRINT AT 5.2; “APPROACHING G E ANSWERED BY“ 
235 FOR A=1 TO 4 JR SOLAR" 2 : 36@ PRINT AT 12.2: "ENTERING A F 
240 PLOT 2.A LSD PRINT AT 7.2; "SYSTEM. I NIL LANET NAME." 
245 NEXT A L TAKE" a Xs 370 PRINT AT 14,2; "ARE YOU REAL 
250 FOR A=1 TO 4 478 PRINT AT 2.2: "CONTROL OF 7TH Y, CREW? Y OR 
255 PLOT 22.A E SHIF FOR” S380 INPUT B$ 
250 NEXT A 48@ PRINT AT 2,2; “DECELERATIGN 8900 IF Be="Y" THEN GOTO 990 
265 FOR A=1 TO 4 TO DOCKING" S@@ IF BS="N" THEN GOTO 940 
270 PLOT 44.A 498 PRINT AT 18.2; “APPROACH FOR 320 IF B&<>o"N" THEN GOSUB 300G 
275 NEXT A MOON BASE 2." 230 GOTO 870 
2680 FOR A=1 TO 4 495 PRINT AT 26.25; “ALEC “ 348 GOSUB 2500 
285 PLOT 66.89 S@@ PRINT AT 11,2; "I WILL DE-ca 850 GOTO 3500 
290 NEXT A NTROL AT 1000' $99@ PRINT AT 20.23," Š 
295 FOR A=1 TO 321 S510 PRINT AT 12.2; "MPH TO LET T 392 PRINT AT 20.1: SA; TAB 6; “ne 
300 PLOT 1,1@+A HE DOCKING" H “3; TAB _12:;5C; TAB 27; "/MPH “; TRE 
385 NEXT A S2e@ PRINT AT 13.2; “COMPUTER TAK. 233 "ALEC" 
310 FOR A=1 TO 321 E CONTROL OF" 100a GOSUB 2aee@ ; 
315 PLOT 6&0, 10+A S30 PRINT AT 14,2; “THE SHIP. OU 1@@3 PRINT AT 2.13 “NAME THE PLAN 
320 NEXT A AA R ETA IS--AWK?" ET THAT: 
322 PRINT AT 28.1; “SPEED(ACT)". S4@ PRINT AT 15.2; "x=MARY HAD A igi LET GR=INT (RND*27} +1 
TAB 12; “SPEED (Gat) *; TAB 23; “CONT 2 F141=<2//7BLEEP?7" 3415 IF @R=K THEN GOTO 1010 
ROL" 550 PAUSE 1500 i@2@ LET K=0R : ‘x 
S23 IF P=i THEN GOTO 220 ne S53 LET H= 1@25 IF O@R<=S THEN LET Q$=" MERCU 
324 PRINT _AT 20,1; “HYPER-WARP 555 GOSVUB 2000 ny" 
TAB 12; “HYPER- -VARP*; TAB 23; ALES 640 PRINT AT 2.2; “PROFESSOR CYP ARQ IF @R>3 AND OR<=6 THEN LET 
HER HERE-ALEC. Rs VENUS” 3 
325 PAUSE 750 65@ PRINT AT S.2: "YOU HAVE NOT 14235 IF OR>6& AND GR<=9 THEN LET 
330 SLOW SEEN STUDYING" $= EARTH" 
333 PRINT AT 3.2; “ALEC HERE-PRE 66Q@ PRINT AT 4,2; “YOUR INFORMAT 1340 IF GR:+G AND GFR<=12 THEN LET 
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CRMAL SPACE" ANSWERS ON" T 8§$="JUPITER* 
335 PRINT AT 5,2; “IN 27 SECONDS * 580 PRINT AT 6,2: “ALL THE QUEST 1850 IF OR>15 AND GR<=28 THEN LE 
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60 SYNC Magazine 


L387 GOTO 1350 


Eo a 


1855 IF G@R:1if AND O@R<=22 THEN LE 1400 LET SG=SC-S0O 2. a 
T D- URANUS” 1255 GOTO 1350 1420 PRINT AT 20.12; 
i968 IF GR:+21 AND @Rc=24 THEN LE 2256 PRINT AT 3.2: “REVOLVES ARGU 2430 PRINT AT 26,12:5C 
igen Tr OR Si. 27 THEN LE a Z BRINT aT 4,2 EVERY 11.86 PEE Te SO? 21820 THEN GOTO 1458 
2885 QR<= E he a Y = = 
=*3e-"PLuTo" OND 125 ; i449 IF SC:1000 THEN GOSUB 2500 
137A LET G=1258+ (ORe4; T259 "GOTO 1350 1445 GOSUB 3500 
z275 GOTO ® L260 PRINT AT 3.2; “HAS A MAJOR M i468 GOSUB 20800 
ee ae one ae eS Toe NORINT 1590 REM SAFE LANDING 
To 18 “TS 5 ii 44 AT 4.2; “EUROPA. 
INE FROM THE: °° FIRST IN L $555 GOTO 135e 4539 PRINT AT 5@,25; DOCKING" 
1205 PRINT AT 4.2; "SUN." 1264 PRINT AT 3.2: “IS 6TH IN LIN 1520 PAUSE 258 

1207 GOTO 1358 — £ FROM THE SUN.“ 1535 GOSUB 209909 — 

2098 PRINT AT 2.2; "REVOLUES ARDOU 1267 GOTO iss 1546 PRINT AT 2.8: “222 ECONGRAT 
ND THE SUN ONCE“ — 1258 PRINT AT _S.2:;°5S THE 2ND LA VJLAT IONS ££€22# eat 
1209 PRINT AT 4.2: “EVERY 88 DAYÈ RGEST PLANET IN“ 1550 PRINT AT 4.2: “YOU RAVE SURU 
ai R 4269 PRINT AT 4.2: "GUR SOLAR SYS IVED THE i 
1211 GOTO 1350 aoe eee sem eee ne wee Ae CRISIS. PREPA 
3545 ` : “HAS A SURFACE 127 = a Re: a 

*SEMPERATURE DP 1272 PRINT AT 3.8: “HAS SEVEN RIN 1570 PRINT AT 2i “SAFE LANDING 
1213 PRINT AT 4.2; "430 DEG. © ON $3." iste Goes sake 
Le igh ee Pe a ae isos PRINT AT 3, 2; “IS 7TH IN LIN 1590 GOSUB 3520 
Ae. TEn TAr e DETE > PRON TE SNOS 7 ` 1998 REM NEXT LINE ENDS PROGRAM 
42 12 1279 GOTO 1359 
ibis PRINT AT 3.2; "IS 2@ND IN LIN 1280 PRINT AT 3.2: “HAS NINE RING sone Eines SHIP "S SCREEN 
= u 5 ac Sd =: 
i219 GoTo 1350 1283 GOTO 1350 2920 LET H=2 
TH THICK CLOUDS” L -2:5" 
: p. 32 AT 4,2: “DEG. C AT THE 2348 LET H=H+ti 
Seat es ee ene ‘Stroup Tops > S 2 ai 22350 IF H>=16 THEN GOTO 2085 
2223 GOTO 1350 12897 GOTO 1350 re 2360 GOTO 2030 
i224 PRINT AT 3.2: “REVOLVES ARGU i288 PRINT AT 3.2; "IS STH IN LIN 2255 SLOW 
ND THE SUN ONCE” = FROM THE SUN.“ 2090 RETURN _ ho 
2225 PRINT AT 4.2; “EVERY 225 DAY 13912 GOTO 1359 p 2500 REM CRASH MESSAGE 
Ss 1292 PRINT &T 3.23: “HES A MOON HE: 2585 GOSUB 2899 3 y. 

i227 GOTO 1350 MED-TRITON." 2510 PRINT AT 2.2; “ALL HOPE IS G 
4228 PRINT AT 3.2; "IS SRD IN LIN 1295 GOTO 1950 Hi- DNE.’ ri Ri 
£ FROM THE SUN.“ 1236 PRINT AT 3.2; “REVOLVES ARDU 2512 PRINT AT 3.2; “PREPARE FOR © 
4231 GOTO i359 NO THE SUN OéCE* TSASTER. - snes 
1i UE Fe L207 PRI AT 4.2; “EvUERY 165 VES 
LANET RNGUN ton’ n TS ae ees aa RE. ; 2520 PRINT AT 6.2; “GOORBY Goor 
“ae È 1229 GOTO 1356 =$ 
1233 PRINT AT 4,2; “SUPPORT LIFE Ea ree ees a a a A Praa eee Ne an i 
1235 GOTO 1550 = FROM THE SUN.” 2540 PRINT AT 24.124: “£eCRASHEs 
1296 PRINT AT S.2;“IS 149.600,06 3383 GOTO 1356 oe 2545 PRUSE 250 
a KM FROM THE“ i304 PRINT AT 3.2: “IS THE SMALLE 2550 RETURN 

8237 PRINT AT 4,.2:“SUN. (APPROX. ST PLANET IN“ 3200 REM IMPROPER INEUT ROUTINE 
93 MILLION" 1305 PRINT AT 4.2: “OUR SOLAR SYS S881 GOSUB 2899 
1238 PRINT AT 5.2; “MILES.)" TEM: SS8iG@ PRINT AT 2,2; “IMPROPER INE 


1240 PRINT AT 3.2;"IS 4TH IN LIN 3306 PRINT AT 3.2; “HAS A MOON NA 3226 PAUSE 500 

= FROM THE SUN.” HED -CHARON. ` 230 GOSUB 2000 

i344 BRINT AF 1359 PRINT AT 5,2 YOUR ANSHE 3500 CLS 

244 PRINT AT 3,2; “IS KNOW - i ,a5" WE 35 
AE RED PLANET. =" Oe te) Nee ae 3510 PRINT “OO YOU VISH TO PLAY 
1247 GOTO 1350 2354 PRINT AT 1@.28; “CORRECT ANSI 435A IN?" sf 

1248 PRINT AT 3.2; “HAS A VARIABL ER-"j; 0 3515 PRINT “Y OR N 
E SURFACE" iSSS IF A$=0$ THEN GOTO 13565 3528 INPUT Bẹ 

1249 PRINT AT 4,2; “TEMPERATURE A 1360 IF _A&€<>Se THEN GOTO 1990 3533 IF Be="Y" THEN GOTO 3570 
UERAGING MINUS“ 1565 LET SA=5A-1900_ S223 IF Bg="N° THEN GOTO 1399 
$258 PRINT AT 5.2: "5@ DEG C.“ 1375 PRINT AT 20.1; ° i S550 IF BEco"N" THEN GOSUB 3000 
1851 GOTO 1350 i385 PRINT AT 20.1 5A 3568 GOTO 3500 

1252 PRINT AT 3,.2;"IS STH IN LIN 1390 IF SA¢=190@ AND SC>=1000 TH 2570 LET P=i 

€E FROM THE SUN.“ EN GOTO 1500 33588 GOTO 26 


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January/February 1983 61 


speeded up by using a fixed star field, but 
I decided to keep the random generator 
because it is such a good visual represen- 
tation of the RND function. I did not use 
the inhibit instructions with this particular 
RND statement, so it will run freely, gen- 
erating what it will. 

Some of you may wish to view the 
generation of the star field in the SLOW 
mode. To do this, change line 338 FAST 
to 338 SLOW, and add 392 STOP. The 
program will progress through the star 
field in SLOW mode, and then STOP. To 
see it again, just press RUN and ENTER 
and a new star field will be generated. 

The star field random generator is in 

342 LET J=INT(RND*10)+1 

You might want to vary the density of 
the star field by changing the value of the 
multiplier. I used a multiplier of 10 
because it produced a star field that was 
pleasing to me. If you decrease the multi- 
plier, the density will increase. If you 
increase the multiplier, the density will 
decrease. In any event, I think you will 
find it as fascinating as I did. 

I mentioned before that this RND func- 
tion was not inhibited. While using a 
multiplier of 5, the random generator 
produced 5 stars in a row on one star 
field. This indicated that the number 1 
had repeated immediately five times. This 
is the highest number I saw. Perhaps you 
will see more. 


responds with: 
1. Azimuth and Altitude 


2. Right Ascension and Declination (for astronomers) 
3. Simple compass coordinates (for beginners) 
4. GRAPHIC DISPLAY of planet in current 


constellation 


5. LOCAL sidereal (star) time to aid in finding stars, 


comets, nebulas, etc. 


Own or give this incredible program and reap the harvest of real 
understanding forever! Comes on quality cassette with docu- 
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EPHEMERIS V, P.O. BOX 261, Winchester, KY 40391. 


62 


PLANET FINDER FORTHE 16K TS-1000/ZX-81 


MERCURY, VENUS, MARS, JUPITER and 
SATURN are all visible to the naked eye. The ancients 
recognized that their special quality is that they move against 
the background of “fixed” stars. Predicting their movements 
has been the preoccupation of geniuses for thousands of 
years. Now these movements are well understood, buy only by 
a few dedicated observers. Ephemeris V is designed for these 
people and others (ages 12 and up) who wish to join them in 
this pursuit of basic knowledge. 16K reqd. 

ENTER: date, time, lat. and long. (Lat. and long. can be 
perm.) Then choose a planet. In seconds Ephemeris V 


The random generator used for the 
selection of questions is inhibited. This 
generator is in 

1010 LET QR=INT(RND*27)+1 
The inhibit statements are: 

1015 IF QR=K THEN GOTO 1010 

1020 LET K=QR 

Inhibiting the star field generator would 
have reduced the realistic look for the 
star field, but not inhibiting the question 
generator would have allowed the same 
question to repeat one or more times 
with the result that the whole program 
would have looked silly. 


In Closing 

I would like to wax philosophical on 
the subject of “randomness” for a 
moment, and ask the question: Is it pos- 
sible to find true randomness in this three- 
dimensional, two-state universe? It would 
seem that a tree being struck by lightning 
would be a truly random event. But, on 
reflection, a tree standing in the middle 
of a thunderstorm would have a good 
chance of being struck, while a tree stand- 
ing under a sun-bright, cloudless sky 
would not have any chance at all. So, 
here too, is a condition—the tree must be 


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standing in a thunderstorm in order to 
have a chance of being struck by light- 
ning. True randomness may exist, but I 
believe, now, that it will not be imme- 
diately obvious. 


Notes: 

1) The graphics characters and other 
elements used in “Space Crisis” are: 

350: Inverse asterisk. 

355: Inverse space. 

1353: Three spaces before 
YOUR... 

2030: 29 normal spaces between quota- 
tion marks. 

2) An underlined word in a program 
indicates that it is a single-stroke keyword 
or function. 

3) I would recommend that you write 
the program and, after de-bugging, SAVE 
it before you do any of the modifications 
that I suggest in the article. 


“HAR 


Ed. — For the convenience of our readers 
the author will supply Listings 1 and 3 on 
cassette for $3 including postage. Readers 
outside the U.S. should include in the 
payment enough to cover the additional 
cost of postage for about 2 ounces. Ma 


ZX81 workstation isa 


SYNC Magazine 


DON'T TAKE OUR WORD FOR IT... 


READ THE REVIEWS 


UNDERSTANDING YOUR ZX81 ROM 

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As Easy As 2+2 Harry Doakes 


Ever thought about learning to program in 
machine code? 

Maybe you have. Maybe you even got far 
enough to open one of those thick books full 
of jargon and technical details. Maybe you got 
far enough into it to be scared away. 

But chances are, you just could not make 
any sense of it. All the talk about hexadecimal 
and bus structures and pseudo-ops and 
gobbledygook .... 

Let us try a different approach. Machine 
code programming is, first of all, program- 
ming. You already know how to program in 
Basic; that means you are already on the way 
to programming in machine language. 


What Is in a Name? 

Every language has a name. Some lan- 
guages have more names than they really 
need, and that is the case with machine code 
programming. 

You may hear people talk about 
mnemonics, or source code, or assembler 
code, or assembly language. They will also 
refer to object code, or numerical code, or hex 
code. 

Do not panic—it is all the same thing. 

Take a look at Figure 1. On the left is a string 
of numbers, while on the right we see some- 
thing that looks like a regular sort of pro- 
gramming language. They both represent the 
same program. The numerical version is for 
the Z80 microprocessor, the “brain” of your 
computer—it only understands numbers. 
Since it is a little tough for human beings to 
remember what all those numbers mean, the 
version on the right translates the program 
into words. But—line for line—both versions 
mean exactly the same thing. 

It is easier for us to use a word like “ADD” 
than to remember what function 198 does, so 
we write machine code programs in this more 
human kind of language. Then it is a simple 
matter to convert each line into the numbers 
the computer understands. This way, no one 
has to remember the numbers; for machine 
code programming, you only need to learn a 
new programming language that uses words 
you can recognize. 


Harry Doakes, PO Box 10860, Chicago, IL 60610. 


64 


Figure 1. Machine Code Program. __ 


42, 12, 64 LD HL, (16396) 
22, 22 LD D, 22 

1, 254, 0 LD BC, 254 
35 LOOP: INC HL 

126 LD A, (HL) 
254, 118 CP 118 

40, 10 JR Z, NEXT 
198, 128 ADD A, 128 
119 LD (HL), a 
237, 120 IN A, (C) 
254, 63 CP 63 

192 RET NZ 

24, -16 JR LOOP 

21 NEXT: DEC D 

32, -19 JR NZ, LOOP 
201 RET 

Why Me? 


Maybe you are thinking one taste of this is 
enough. Why should anybody have to go 
through all the trouble of figuring out this ar- 
cane language; except for a few things—such 
as “loop” and “next”’—this is not even En- 
glish. Maybe it is a better idea to stick to 
Basic. 

Well ... remember the first time you saw a 
computer program? Even if it was in Basic, 
you probably could not figure out what it 
meant. That is because Basic is another lan- 
guage; though it is similar to English, and 
uses English words, you had to learn a whole 
new set of rules for using the words. 

Although it may not look much like it, that 
“human ” version in Figure 1 is full of English 
words, too. You probably do not recognize 
them because they are all abbreviations. Some 
are for familiar words that mean just what they 
sound like: “RET” means “return,” which is 
the same as in Basic—it is for returning from 
a subroutine. “CP” is “compare,” for com- 
paring one number to another. 

Why should you learn a whole new lan- 
guage when you already know Basic? The an- 
swer is simple. Machine code is compact. 
Machine code is powerful. Most of all, ma- 
chine code is fast. 

How fast? Well, let’s try this program and 
see. 


A Day at the Races 

If your Sinclair computer cannot operate in 
SLOW mode, this demonstration might not be 
very impressive. But follow along anyway; it 
works with either the 4K or 8K ROM. 

First, we cannot enter machine code di- 
rectly into the computer. It will accept com- 
mands only in Basic. So we must make some 
space for the routine. With the 4K ROM you 
can do that by typing 

PRINT USR (620) 

That will reserve 12 bytes of memory at the 
top of RAM. This program is longer than that, 
so you will need to do it twice more. Be sure 
you type it in each time. You cannot just make 
a program out of it, because it works like a 
NEW command—it wipes out the whole pro- 
gram each time it runs. 

With the 8K ROM, run this short program: 

10 POKE 16388,-30 

20 POKE 16389, PEEK 16389-1 

30 NEW 
That will give you 30 bytes of space at the top. 
You can change the amount of space you have 
by changing the POKE in line 10. 

We will use the Basic program in Listing 1 
to get our machine code routine working. 
Type it in—but do not run it yet! (If you have 
the 4K ROM, remember to use parentheses 
with all the functions.) 


Listing 1. Loader Program for 
Machine Code Program. 


10 LET Q=17380 

20 FOR A=O TO 27 

30 PRINT A; “########”: 
40 INPUT B 

50 POKE A+Q,B 

60 PRINT PEEK (A+Q), 
70 NEXT A 

80 FOR A=1 TO 100 

90 NEXT A 

100 LET B=USR Q 

110 STOP 


The program in Listing 1 is designed for 1K 
RAM. That is what comes on a ZX80 or 
ZX81. If you have a Timex/Sinclair 1000, you 


SYNC Magazine 


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have 2K RAM, and you should change line 10 
to read 

10 LET Q=18404 
If you are using a 16K RAM module, change it 
to 

10 LET Q=32740 

Now run the program, and enter the num- 
bers in the left column of Figure 1. When you 
get to the last number, the screen should look 
like this: 


0 42 1 le 
Zz 64 3 22 
“ 22 5 1 
6 254 7 0 
8 35 9 126 
10 254 l1 118 
12 40 13 10 
14 198 15 128 
16 119 17 237 
18 120 19 254 
20 63 21 192 
22 24 23 240 
24 21 25 32 
26 237 a 201 


If you have typed a wrong number, hit 
BREAK and start again. 

Now hit ENTER (or NEW LINE) again, 
and watch what happens. 

What did happen? Suddenly—very 
suddenly—the whole screen was reversed. 

That is the speed of machine code. It is the 
fastest that the computer can work. 


PROGRAM FASTER! 


There is even a way to test how fast it really 
is. You can stop a program in Basic by hitting 
the BREAK key. This machine code routine 
can be stopped by hitting any key while it is 
running. 

So run the program again—and this time, 
as soon as you see it starting to reverse the 
screen, hit a key to stop it. Good luck trying to 
catch it, though—it runs very, very fast. 


Riding the Fast Track 

What exactly is going on here? One way to 
get an idea is to look at a Basic version of the 
machine code routine. It is in Listing 2. 


Listing 2. Basic Version of Figure 1. 


200 LET D=22 
210 LET H=PEEK 1696+256*PEEK 
16397 


220 LET H=H+1 

230 LET A=PEEK H 

240 IF A=118 THEN GOTO 280 
250 LET A=A+128 

260 POKE H, A 

270 GOTO 220 

280 LET D=D-1 

290 IF D>O THEN GOTO 220 
300 RETURN 


The subroutine works by using one of the 
Basic system variables, a number called 


D-FILE. This tells the computer where, in 
memory, what is on the TV screen is kept. 
Then the program runs through all 22 lines of 
the display (that is why D equals 22 to begin 
with). It adds 128 to the value of each charac- 
ter (that is, reverses it) except for the special, 
invisible NEWLINE character at the end of 
each line (that is the IF in line 240). 

Even if you do not quite follow exactly how 
it works, you can type it in along with the 
program you already have. Replace lines 40 
and 100 with 

40 GOTO 60 

100 GOSUB 200 

You will see the difference. In Basic, it is 
slow. In machine code, it is fast. 

You know what that means. The trouble 
with most programs is they are not fast 
enough. That is especially true with games; it 
seems to take forever for things to move 
around on the screen in Basic. 


You have already seen how fast they can | 


move in machine code. 

Ready to ride the fast track? I will try to 
keep the gobbledygook to a minimum, and 
explain things as we go along. With some 
practice, you will not only be able to run ma- 
chine code programs, but you will also under- 
stand what is going on—and even start writ- 
ing machine code routines yourself. 


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SYNC Magazine 


As Easy As 2 + 2 

Let’s start out with something a little sim- 
pler than that fancy screen-blitzing program: 
adding 2 and 2. In Basic, it is pretty simple: 

LET A=2+2 
will do the trick. With machine code, it is only 
a little more complicated: 

LD A,2 

ADD A,2 

Yes, ADD means just what you think it 
does—but first things first. 

LD is short for “load. ” In Basic you LOAD 
a program (from your cassette recorder). In 
machine code, you “load” a number. As you 
might suspect, “load” is almost exactly like 
LET in Basic. So 

LD A,2 
means the same thing as 

LET A=2 
—both lines put the number 2 into the vari- 
able A. 

... Except that it is not exactly a variable in 
the machine code version. The A is a 
register —a special memory location that is 
located right inside the Z80 microprocessor 
that runs your computer. Unlike a Basic vari- 
able, a register can only hold a number from 0 
to 255. However, being inside the brain of the 
computer, a register can move numbers 
around much faster than a Basic variable can. 

The Z80 has more than 20 registers. Some 
of them we cannot use without crashing the 
system of the Sinclair computer, because they 


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are used almost constantly in the SLOW 
mode. Let’s start out by looking at another 
half dozen registers that we can use. 

Their names are registers B, C, D, E, H, 
and L. (These one-letter names are really just 
for the benefit of programmers. To the com- 
puter, they are all just numbers.) 

The registers work like Basic variables. 
Just as you can 

LEY B=C 
in Basic, you can ~ 

LD B,C 
in machine code. You can load any of these 
registers into any other register. You can also 
load any number from 0 to 255 into any of the 
7 registers—for example, 

LD E,67 

LD H,212 


Bigger and Better | 

Better still, you can load in even bigger 
numbers—up to 65535—by using two regis- 
ters at once. For example, 

LD BC, 32000 
or 

LD HL,999 

Maybe you are wondering how this works. 
After all, you are not just adding these two 
registers together. 65535 is hundreds of times 
higher than 255. 

It works something like regular decimal 
numbers. Suppose you write a number with 
just one digit. The largest number you can 
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When you use two registers, the second 
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But you cannot use just any two registers 
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the pairs are always B and C, D and E, or H 
and L. They are sometimes called the BC reg- 
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register pair, and it is always the first 
register—B, D, or H—that is worth 256 
times its usual value. 

So, for example, if you 

LD BC,32000 
the computer puts 32000/256 (that is 125) into 
register B, and the remainder (in this case, 0) 
into register C. It has the same effect as 

LD B,125 

LD C,0 
except it is only one instruction instead of 
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LD HL,999 
has the same effect as 

LD H,3 

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67 


Maybe you have noticed that register A is 
not part of a register pair. It has not really been 
left out: register A is special. It can do lots of 
things that the other registers cannot. 

Like adding, for instance. 


Add Another Instruction 

In Basic you can add to any variable. In 
machine code, though, you can only add to 
one of the registers, register A. You can also 
add to just one of the register pairs—the HL 
register pair. 

In other words, you can say 

ADD A,B 
which works like 

LET A=A+B 
in Basic. Likewise, you can say 

ADD HL,BC 
which in Basic might be 

LET HESHLABC 

Do not get confused, though. You can only 
add a single register, or a number from 0 to 
255, to register A, and you can only add a 
register pair. You cannot mix the two 
kinds—for example, you cannot add register 
pair A directly to register pair HL. 

What if you wanted to add register A to 
register pair HL? You might do it like this: 

LD B,0 

LDC,A 

ADD HL,BC 

Once you have copied what is in register A 
into the BC register pair, you can add that to 
HL with no trouble. 

What if you wanted to add register A to 
register pair HL? You might do it like this: 

LD B,O 

LD C,A 

ADD HL,BC 

Once you have copied what is in register A 
into the BC register pair, you can add that to 
HL with no trouble. 


USR Friendly 

Maybe you are feeling a little overloaded 
with machine code just now. Well, take a deep 
breath and relax for a moment, while we talk 
about something in Basic: the USR function. 

USR is how we can run a machine code 
subroutine in the middle of a Basic program. 
When the computer hits a line like 

PRINT USR 17380 

it stops what it is doing and goes to work on 
the machine code routine beginning at mem- 
ory location 17380. 

It keeps working on it until it hits a RET 
instruction—the machine code ‘“‘return.” 
Then it returns to Basic, and picks up where it 


68 


left off. This is a lot like GOSUB—only the 
subroutine is machine code, not Basic. 

But wait—that line has a PRINT in it. 
What gets PRINTed on the display? 

That depends. If you have the 8K ROM, the 
computer PRINTs the number that was in the 
BC register pair. If you are using the 4K 
ROM, it PRINTs the HL register pair. 

You can use the USR function just like any 
other number. For example, you might say 

LET A=USR 17380 
or even 

PRINT CHR$ (USR 17380) 

This is very handy because it means that we 
can solve a problem in a machine code sub- 
routine and then send the answer back to our 
main Basic program by loading the answer 
into HL or BC before we return to Basic. 


It All Adds Up 

Ready to add 2 and 2 now? Here is how we 
will do it—first, the addition: 

LD A,2 | 

ADD A,2 

Then the result goes in register pair BC for 
the return to Basic: 

LD B,O 

LDC,A 

For the benefit of 4K ROM users, we will 
put it in HL, too: 

LD H,B 

LY EC 

Finally, we return to Basic: 

RET 

Figure 2 shows this program, along with 
the numerical version the computer under- 
stands. (You can check the numbers in the 
appendix section of your ZX81 or T/S 1000 
manual, under the heading ““The Character 
Set. ”) 


Figure 2. Machine Code Program 
for Adding 2 and 2. 


62, 2 LD A,2 
198, 2 ADD A,2 
6,0 LD B,O 
79 LD C,A 
96 LD HB 
105 EDLC 
201 RET 


Now you are ready to run it. 

First, reserve space at the top of memory, 
as you did for the previous program. Then 
carefully type in the program in Listing 3. If 
you are using a system with more than 1K 
RAM, remember to change line 10 accord- 


ingly. 


—— Listing 3. Loader Program for Figure 2.___ 


10 LET Q=17380 
20 FOR A=0 TO 9 

30 PRINT A, 

40 INPUT B 

50 POKE A+Q,B 

60 PRINT PEEK (A+Q) 
70 NEXT A 


Now run the program and type in the ten 
numbers in Figure 2. When you are finished, 
check carefully to make sure you have every- 
thing in the right order. It should look like this: 

62 

2 

198 

2 

6 

Os 

79 

96 

105 

201 
Now you are ready. Type 
PRINT USR Q 
and the answer on your screen should be— 
surprise! —4. 

Care to experiment? You can add two dif- 
ferent numbers together. Just change the 2’s to 
other values. To add 7 and 3, for example, run 
the program in Listing 3 again. This time, the 
first four numbers you type should be 


OAANNKNMNHRWNK © 


0 62 
1 7 

2 198 
3 3 


The rest of the numbers are as before. Typ 

PRINT USR Q ; 
again to get the new result. 

Try your own numbers. Remember, they 
should be between 0 and 255. If you use large 
numbers, notice what happens when the sum 
is larger than 255. 


Coming Attractions 

Adding 2 and 2 may not seem like a big 
deal—but it is just the beginning. Next time 
we will take a look at loops, and see how fast 
machine code can really run. 

If you have comments or questions about 
machine code programming, or something is 
not quite clear, let me hear from you. Be sure 
to send along a stamped, self-addressed en- 
velope if you need a reply. =i 


SYNC Magazine 


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Sinclair Hi-Res Graphics 
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eri ter Sy g? ems 


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The ZX-G gives your ZX-81 the ability to create memory- 


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70 


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UARY 1983. 


POWERTRONIXS INTRODUCES 
PTX-I/O-an expandable 0 to 16 port input/output 
system. 


The PTX-1/O-CM control moduel allows the ZX-81/ 
TS1000 user to input and output the 8 bit TTL data 
between the computer and peripherals. 

It will also drive a total of 8 output and 8 input ports, 16 
TOTAL, each 8 bit TTL data. 

The PTX-I/O-CM comes complete with one input and 
one output port each with LED display of data. 

Use it to interface ASCII printers keyboards, plotters, 
joysticks, etc. 

D/A, A/D and other moduels are available. 

Special introductory price of only $45.95 assembled 
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—** 2K memory for the ZX-81 computer. Gives over 6 
times original computing power only $11.95 

*SALE* ZX81/TS1000 REAR CONNECTORS 23 
pins (46 contacts) P.C. mount - will also accept wires. 
Only $5.25 each/5 for $23.50. 

Shipping charges under $11 add $1.50 under $25 
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8K ROM 
1K RAM 


8K Machine Code Keyboard 
Scanning Sidney Belman 


Bernard Puerzer’s program for scanning 
the ZX80 keyboard (“Machine Code Key- 
board Scanning Program,”SYNC 1:4) was 
written for the 4K ROM. His program 
served as the occasion to give the same 
ability to read the keyboard to 8K ROM 
users. This required adaptation since the 
programs are not automatically transfer- 
able. One of the problems was to get 
around the differences in the way that 
the index registers are used. This program 
avoids that problem. Further, it adds a 
WAIT loop which keeps the screen dark 
after ENTER is pressed and then prints 
the keyboard entry following ENTER. 
This loop is in addresses 20023 to 20026. 
It requires that ENTER be read first in 
addresses 20002 to 20016. 

The port of entry from the keyboard is 
IN A,(FE) at address 20014. The keyboard 
enters as groups of 5 keys determined by 
which bit of A is off, i.e., equals zero. 
Thus, LD A,254 (before IN A,254) allows 
keys “Shift to V” to enter. Table 1 
describes this situation. The key enters A 
with values as shown in the last column. 


Note that the values are from the peri- 


phery to the center. A binary representa- 
tion of each number will show how the 0 
bit shifts. 

The group values are stored in address 
25000, and the key values in address 
25001. Addresses 20030-20064 calculate 
the address containing the codes for the 
keys which are stored in HL and the codes 
are transferred to address 25005 by 
addresses 20065 to 20068. Address 20069 
is the RET. The codes are stored in 
addresses 20070 to 20109, in identical 
order as given by Puerzer. My address 
20070 = his 17458, etc. I prefer to use 184 
(inverse S) for Shift and 179 (inverse N) 
for ENTER. 


Sidney Belman, 376 Edgewood Ave., Teaneck, 


NJ 07666. 


To enter the code you can use the 
loader program in Listing 1. To run the 
program I use this routine: 

200 LET K USR 20000 

210 PRINT CHR$ (PEEK 25005) 

220 STOP 

230 GOTO 200 
I enter GOTO 200, press ENTER, and 
then press the desired key. CONT will 
repeat the program. a 


Table 1. 
247 ie ho Ve Gein Gh. 
nia ge TEE =r 
47 
Pode Ps OQ i S ya same 
Zao j A to G same 
24 C) Shift. 
TON Sane 
ERF 4 O toe same 
Zoo S P e h i same 
191 È N/L to H same 
r27 7 Space 
to &B Same 


Figure 1. Machine code Loading Program. 
(From Bernard Puerzer’s article.) 


5 LET MARK=0 
10 PRINT “ENTER STARTING 
ADDRESS” 
20 INPUT A 
30 PRINT A; “ (1 sp.) ”; PEEK (A) 
40 INPUT B 
60 IF B>255 THEN GO TO 130 
70 POKE A.B 
80 PRINT A; “(1 sp.) ”; PEEK (A) 
90 LET MARK=MARK +1 
100 IF MARK < 10 THEN GO TO 110 
105 CLS 
107 LET MARK = 0 
109 PRINT A; “ (1 sp.) ”; PEEK (A) 
110 LET A = A+1 
120 GO TO 30 
130 STOP 


SYNC Magazine 


IS YOUR FAMILY TIRED 


Figure 3. Table from Puerzer’s Article. 


17459 63 17469 60 17478 28 17488 231 
17460 6l 17470 42 17479 37 17489 49 PEN Iau 
17461 40 17471 59 17480 36 17490 48 INTELLECT? 
17462 59 17472 sf 17481 35 17491 47 | 
17463 38 17473 29 17482 34 i7492 45 INTELI-QUIZ IS THE SOLUTION! 
17464 56 17474 30 17483. 53 17493 0 Through INTELI-QUIZ you can test 
17465 4 17475 31 17484 52 17494 5 OE a; O E RE T 
17466 43 17476 32 17485 46 17495 50 es 
17467 44 Page: 132 17486 58 17496 = 51 ; ANAE Aa 
17468 34 EIAN 33 17487 62 17497 39 issue 1.1 “General Knowledge” $5.00 each 
issue 1.1 “Movie Trivia” $6.00 each 
Figure 2. 8K Keyboard Scanning Program. issue 1.1 “Sports Trivia” $6.00 each 
Send Check or Money Order to: 
Address Hex Decimal Comments SCI. 
ZOQ00 OE 14 ade 2. Box 553 
20004 i 1 Mechanicsville, Virginia 23111 
20002 6 6 LD B191 entry: for N/L Virginia Residents add 4% sales tax. 
SOOO RE i9i Overseas orders add $1.00. 
2000A 18 z4 JR 4 
20005 4 4 
POGUE TOA RECUR 
2OQO07 Ot) {) 
209008 Or, 14 toy “OQ 
ZOOOD (8) ©) 
eOOTO 78 T20 LD A,B group entry code 
20011 SE 30 LD 025000). 
ZOO LR AS 168 
SOO 6&1 7 
20014 DE Eg ke IN A, (254) port for keyboard 
2OOTS PE 4 
ZOOL Pe at Cr GS 
20017 or 63 
20018 28 40 JR Z -14 loop to 20006 
ZUOLe im 42 
2002A 8i P27 ADD A,C 
2OO21 FE a4 P e 
EO ES i 6A 
SGA eg Ai) A a N Agee | loop until next key 
Joo ER PR 
ZOLI ot 143 BURLE . 
2PONŽÓ a we) LD (25001).,A store key value 
20027 AF 149 
29029 &1 7 
ZOO LT OO i NOF 
SOOO ak ne LDH, 20069 start calc. address 
DIOS 45 iol 
PARLE 4E 78 
INOS ‘7 i7 LD DE,.S Address Hex Decimal Comment 
20034 Oo wd 2003S Có 198 ADD A, 192 
20035 D 8) 20056 CO 192 
TOAG FA wet LD A, (25000) 20057 OS é LD sack 
Fa Sh aD Ag toe” SOOS8 7E L27 
ZOO3E 6i FA ZOT CR LO ROC B 
DODAT Me É LD B, 254 ZOOSO OO E) 
TO4O FE 24 20061 19 Kar ADD HL, DE 
Jong i 18 24 JR 3 LOO? Ra. 184 CFORK 
20042 Om Ks ZOOGS 20 Beta FRNA 76 
PODGER CE DS RG se =0064 FĀ Eja 9 
20044 OO Q 20065 Fi = Teg LD A, CHL) code inta A 
2OO8S 19 Pk) ADD HL. DE 29066 me TO LD (25005),A | 
eOO4S B8 184 EFEN 20067 AD EZA 
20047 a Se oN mg 29068 éi 97 
29048 FA Paar 20069 i? 2O1 RET 
20049 ii i7 LD DE, 20070 Enter codes given by Fuerzer 
20030 Dİ 1 starting with his address 17438. 
2008 4 DÜ © keep the same sequence, but 
200382 =A 38 LD A, (25001) disregard the addresses given. 
2O0S3 A? 149 See Figure 3. 
20054 6i 97 20109 Last entry 


eee S ee ee ee E SS a nS nS ac SI Ss eS Se 


January/February 1983 


71 


LET YOUR ZX81/TIMEX 1000 WORK FOR YOU 


PERSONAL AND BUSINESS PROGRAMS: 
Are on cassette, are menu driven and save on tape automati- 
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SALES FILE 64K: 
Same as above except it will hold up to 600 products for up to 
100 accounts. 
*** A must for a larger business. *** ------------------- $19.95 
CHECKING 16K: 
Lists up to 25 deposits showing amount of deposit and date 
entered.—Lists up to 80 checks and displays check number, 
date and to whom check was written. Lists by account.— 
Keeps a running total of checks written and the balance left in 
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es.—Search for a chetk by check number, name, date or 
amount to find any check quickly. 
*** Great for tax records. *** ------------------------------ $9.95 
MAILING LIST 16K: 
Holds up to 100 names, addresses and telephone numbers. 
Search by name, city, zip code, or phone number to find any 
address or phone number quickly. Lists all names, changes or 
deletes. 
* Christmas cards are a snap with this program. * ---- $9.95 
INVENTORY (1) 16K: 
May be used for everything from keeping an accurate invento- 
ry for your business, to your personal record collection.— 
Holds up to 150 items with comments for each.—Comments 
may be used for serial numbers, dates, prices or location. — 
List all items, search for a single item, change or delete any 


item. 

*** Everyone should have an inventory of household items in 

case of fire or theft. *** -------------------------------------- $9.95 
INVENTORY (1) 64K: 

Same as above with up to 750 items. --------------------- $9.95 


INVENTORY (2) 16K: 

Same as above without comments. 

Holds 300 items. ------------------------------------------------- $9.95 
CASH REGISTER 16K: 

Totals, figures sales tax, clears and keeps daily totals. 

* Turn your ZX81/ TIMEX 1000 into a cash register. * $9.95 
APPOINTMENT CALENDAR 16K: 

May be used for everything from reminding you of birthdays to 

business appointments.— Just enter the date and list up to (8) 

appointments per day for up to (31) days. Lets you change or 

delete any appointments. Save all appointments on tape. 

** Keep a permanent record of past appointments. ** $9.95 


EDUCATIONAL PROGRAMS: 
On cassette, menu driven, and require 16K. 
MULTIPLICATION TABLES: 
Allows user to choose the multiplier for up to 50 problems.—A 
large graphic (YES) or (NO) will apear after each problem. — 
Each problem is listed, showing your answer and the correct 
answer. 
*** The fun way to learn. *** ------------------------------- $9.95 
MATH QUIZ: 
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division for up to 50 problems, with 6 difficulty levels. —Each 
problem may be listed with the correct answer. 
*** Great for home or class room. *** ------------------- $9.95 
FLASH SPELLING: 
Enter up to 50 words for your child to learn to spell. You deter- 
mine how long you want the word to be flashed. Misspelled 
words may be listed. 
*** Word files may be saved on tape. *** -------------- $9.95 


Add $1.00 per tape for shipping. 
Indiana residents add 4% sales tax. 
Send Cert. Check, M.O., Visa or MasterCard # w/Exp. Date. 


MasterCard 


Dealer inquiries invited. 


HEATH COMPUTER SERVICES 
950 East—52 South 
Greentown, IN 46936 
Phone 317-628-3130 


Installing a UHF 
Modulator Randall Glidden 


For those of you with a standard ZX81 /Timex-Sinclair 1000, this 
article may not be of much interest since, without any peripheral 
devices, your computer will transmit a clear video display with most 
TVs. However, if you have added an external keyboard, a mother- 
board, or even just a 16K RAM pack you will probably have encoun- 
tered those annoying little bands of interference that just will not go 
away, regardless of how much you reposition your computer or 
fiddle with the fine tuning. The problem arises from the square 
waves generated by all digital circuitry which are picked up very 
nicely at 63 MHz (you guessed it—channel 3). Shielding all com- 
ponents will do much to alleviate the situation, but the hard-core 
computer hack with motherboards, modems, and meters of wire- 
wrap may find it difficult or undesirable to put all that circuitry 
under aluminum. Also, shielding does not usually eliminate the 
problem entirely, as those with a ZX81 and 16K RAM alone will 
probably attest—the video quality is much better without the RAM 
pack plugged in. 

A solution that is relatively inexpensive, easy to do, and (best of 
all) permanent, regardless of how much extra hardware you have, is 
to convert your ZX/TS to transmit over UHF channel 33 (146 MHz). 
At that frequency those nasty little digital spectral (Fourier) compo- 
nents go virtually undetected. It is interesting to note that European 
ZX81’s come with a UHF-33 modulator instead of the VHF 2,3 
found in the American model. 

So if you are willing to invest about $15, a half hour of your time, 
and do not mind invading the inner sanctum of your comput- 
er (which will void the warranty of a factory assembled unit), then 
read on. 

If you consult chapter 25 of ZX8/ Basic Programming, you will 
find a nice photograph of the ZX81 hardware layout. (I assume there 
is a similar photo in the T/S 1000 programming book also.) The 
VHF video modulator is the small silver box in the upper left corner 
of the circuit board. (If you have a sharp eye, you will notice that the 
modulator in the photograph is a UHF modulator.) In this project all 
we need to do is replace this with a UHF channel 33 modulator. 
These are currently available from: Computer Continuum, 301 16th 
Ave., San Francisco, CA. 94118 (cost $15 ppd. with instructions, as 
of this writing). You may be able to find one for less at some discount 
electronics houses if you want to shop around a bit. 

Once you get your channel 33 modulator get a 15-25 watt solder- 
ing iron, some rosin-core solder, a small Phillips-head screwdriver, 
and a pair of needle-nose pliers. Follow the steps below for interfer- 
ence free video! 

1) Assemble all your materials in a clean, well-lit work area. 

2) Remove the circuit board from your computer by removing the 
five Phillips-head screws from the back cover. Three of these screws 
are located under the little rubber pads at the corners. Note that the 
AOS EE a Eh lee es ee 


Randall Glidden, 185 Chiswick Rd., Brighton, MA 02135. 


SYNC Magazine 


two screws at the front corners are shorter than the back three 
screws. Inside you will see two short screws holding the circuit 
board to the front cover. Remove these, carefully noting their exact 
location on the board (important when you reassemble). Carefully 
disconnect the keyboard leads by gently pulling them free. Be care- 
ful not to tear or kink these leads or you will have big problems 
later on. 

3) Locate the modulator (see the photo in chapter 25) and discon- 
nect the three leads from its lower end by heating the solder pads 
with your iron and pulling them free with the needle-nose pliers. Be 
careful not to pull too hard or you may damage the printed circuit 
traces on the board. 

4) At this point the modulator is being held down by two solder 
lugs located on its underside at each end. Heat these from beneath 
the board and pull them free one end at a time. You may have to work 
it free a little bit at a time, heating one end then the other. 

5) With the modulator removed you should be able to see printed 
markings on the circuit board, as noted in Figure 1 (e.g., Fr3, UK 2, 
etc.). Note that there are only two leads on the UHF modulator, one 
protruding from a little insulator (Figure 2). Push the solder lugs of 
the UHF modulator into the holes one at a time while heating. You 


Figure 1. Circuit Board Diagram. 


lead 2 


January/February 1983 


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will notice that the jack for the TV cable is closer to the EAR jack 
than on the other modulator. Add extra solder to the lugs if needed, 
since these are the ground connections and should be secure. 

6) Consulting the figures and the circuit board markings (which I 
hope you read before you soldered the modulator down over them), 
solder the lead from the insulator (lead 1) into the hole at the end of 
the line marked “Fr/UK 1”. This is the 5V power source. Be sure to 
pull the lead through the board and trim any excess wire to prevent 


shorts. 


Figure 2. UHF Video Modulator. 


Fine Tuning Screw 
(should not need 
adjustment) 


TV Cable 
Connector 


solder lug 


7) Solder lead 2 into the hole marked “UK 2” (Figure 1). This is 
the video signal from pin 16 of the Sinclair Computer Logic IC. 

8) Make sure there are no shorts between the leads you have 
soldered and any of the printed circuit traces on the board (check 
both sides). Also be sure your solder joints are good at the leads and 
the solder lugs. 

9) Now it is a good idea to see if the thing works before putting it 
back in its case. Plug the TV cable into the modulator, reposition the 
two leads from the antenna switch box to the UHF leads of your TV, 
turn to UHF channel 33, and plug in your power supply. You should 
see a nice, clear blank screen with the “K” cursor in the lower left 
corner, even without the keyboard hooked up. If you do not, fine 
tune your UHF tuner on the TV, recheck your modulator connections 
(is lead 2 in the right hole?), look for shorts, etc. 

10) Before you can put your computer back together you have to 
cut a new hole in the side of the front cover to accommodate the 
different position of the TV cable jack. Use the mold marks already 
on the case (used with the European ZX’s) as a guide. A piece of stiff 
wire wrapped around the tip of your soldering iron can be used to 
heat-cut a hole very easily. 

11) Plug the keyboard tails into the sockets on the circuit board 
and carefully reposition it onto the mounting posts on the front 
cover. The keyboard tails should loop gently under the board without 
any creases or kinks. Replace the two short screws which hold the 
board to the mounting posts. 

12) Replace the back cover, with the two short screws at the front 
corners and the three longer screws at the back. Put the rubber feet 
back, using a little rubber cement if they are not sticky any more. 

Congratulations! You now have a video display that is crystal- 
clear and readable, even when loaded to the hilt with extra peripheral 
hardware. I hope this article will have also demonstrated to the 
Sinclair user the relative ease with which many hardware modifica- 
tions can be performed, thus greatly enhancing the versatility and 
enjoyment of the ZX81 or T/S 1000. 


SYNC Magazine 


CONVERT YOUR ZX.. 


FULLER MICRO SYSTEMS ADD STYLE, POWER, VERSATILITY 


NON 


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AMAZING ZX81 COMPUTER! 


THE FULLER FD42 SYSTEM 
The ideal Christmas Gift for 
ZX81 users. 


If you already are the proud owner of the fastest selling small computer in q 
the U.S., or maybe have a friend or member of the family who’s a ZX 


fanatic, what better buy is there this Christmas than the famous Fuller FD42 2 


System! It converts your ZX81 into a sturdy, attractive and professional unit, 
with full sized typewriter keyboard. All the Sinclair 
ZX81 keys are duplicated with extra shift and 
new line keys. The professional momentary 
action key switches have a guaranteed life 
of 10° operations, and the whole unit 
comes to you complete with a money 

back guarantee. 

IT’S EVEN CHEAPER IN 
KIT FORM! 

FD 42 keyboard and case kit. 


6 p> +$6 p&p. 
FD 42 keyboard kit 


$3 E +$4p&p. -o | 


IT’S SO EASY 
TO INSTALL! 


į You simply unscrew the ZX 
\ printed circuit board from 

| its base, screw it into the 

| the new FD case, and 

® plug in the keyboard. No 
= soldering or technical 
knowledge required. 


ZX81 MOTHERBOARD 


Also easy to install! The FD system Motherboard fits 
inside the Fuller case and allows expansion to the ZX 


memory and 1/0 facilities 
2 slot $30.95 +$4 p&p. 
3 slot $39.95 +$4 p&p. 


NEW! - Programmable Sound 
Generator - adds exciting new 


sounds to the ZX81 range $39 +54 pap. 
Separate P.S.U. 9 volts @ 2 amps $14-% + s4apap. 
Plug Planner- complete with 3 metres 295 

§ of cable and power jack $36: + $6 p&p. 


Ram Adaptor Board - adapts Sinclair RAM 
pack to fit inside Fuller case 


$19 4.54 pap. 


MICRO 
SYSTEMS 


Mail to: FULL MICRO. SYSTEMS, 
The ZX Centre, Sweeting Street, Liverpool 2. 
England U.K. Telephone: 051-236 6109 


maTurn your ZX81 
from this to this 


for... 
FULLER MEMORY EXPANSION 


a massive boost for your ZX81! 
The basic ZX81 has only 1k of RAM - now you can 
add on an enormous 16 or 64k with our FD Memory 


Modules. 4 95 
haar $ 
+$4 p&p 
ast $59% 
FD16k to fit inside Fuller case 
+$4p&p 
$129% 
FD64k Memory Modul e€ meae 
+$4 p&p 


Please supply the following items: 


wad 


ITEM 


Fuller FD System 42 Keyboard & case 


Fuller FD System 42 (Kit form) 


IEN 
SE bie 
[raarFoSenvonemsee | | 
[ram rorocwenonvewie |_| 
C | | 
ee td 
oros | | 
am Fo Snemna | | 


Mail to FULLER MICRO SYSTEMS, 
The ZX Centre, Sweeting Street, Liverpool 2. 
England U.K. 


a Name 
Address 
City /State/Zip 


t US Dollars 
- i Ge es ee es oe ee ee a 


~~ 


A Cheap and Simple EPROM 


Dan Schaaf 


Programmer 


“What more could I want?” That’s what 
you usually say before you buy something. 
But you learn after you have had it for a while 
that there is a lot more to be wanted. Past 


Dan Schaaf, 306 N. Carroll, Michigan City, IN 


46360. 


ON COMPu Tee —He— ON PROGRAMMER 


issues of SYNC have had several articles to 
remedy heart-felt deficiencies in the Sinclair 
Basics: SCROLLs, PAUSEs, READs, 
DATAs, string handling routines, etc. 

This article will show you how to build an 
add-on device which will allow you to have 
any of these routines, plus any you can design 
yourself, permanently and instantly available 
to you in one 4K EPROM without the need to 


Figure 1. Schematic Diagram. 


[\ +57 


LOAD those routines from tape into the ma- 
chine (a waste of time and of RAM). Those 
interested in peripherals for the Sinclairs 
(floppy disk, electronic typewriters, etc.) can 
design monitors and controllers for those de- 
vices. Eventually you can program indepen- 
dent microprocessors for special purposes. 
An EPROM programmer can become a real 
liberator of the power inherent in the Z80. 
4K EPROMsSs now cost less than $10.00. 4K 
was chosen because of its cost advantage and 
simplicity of programming. 4K is a good 
healthy chunk of memory as witnessed by the 


cz 
4 DoK 
3j A, l4 late 
4] On 
Nz fe] 
an E 
8| GND 
+ SV. 
$ R ES 
**\ FROM PIN7, ICG | Hf Bonet i $ 
(PIN 7, U4 FOR MicgorceE) | Ci mbd 
WAIT —— < ALt Ic's VIEWED GNP, & 
| SER FROM Tor + 
¥* NOT REQ D FoR ‘ > 
2x-3 | : | BRING 12'S 
4) oy, j+ 
Ro NC - NO LONNECTION 
BTfeRies I 


SELES 


a rx: oll DB 
ip Da 


Refer to SYNC 1:1 for ZX80 schematic. 
See the ZX81 manual for the edge con- 


-nector assignment. 


* LONNELT TO LOMPUTER 
LINES 


EFRON 


—~<€-- Goes TO EPGE CONNECTOR 


S o -JUMPER ce SWiTeH 


76 


SYNC Magazine 


... TO THE PROBLEM OF STORING YOUR 
RECORDS, TAPE 


60-unit cassette case. 
1314" h. x 1254" d. x 52” 
w. Compartments are tilted 
back to prevent spillage. 
Includes pressure-sensitive 
labels for titling. $17.95 
each; 3 for $49.95 (E 


(B) 30-unit cassette case. 
1314" high x 614” deep x 


(D) 6-unit 7” reel case. 
8” high x 714” deep x 5” 
wide. Holds reels in original 
boxes. $6.95 each; 3 for 
$18.50 


— 


20-unit 12” record case. 
1314” high x 1214” deep x 
344" bi ge ii records in 
original jackets. $7.50 h; 
51," wide. Tilted compart- - l $ AT 


| 3 for $19.95 
ments, labels included. 
$12.95 each; 3 for $34.95 (F) Magazine Case—Magazines 
insert in cases. Designed to 
hold approximately 12 issues. 
$5.95 each; 3 for $16; 6 for 
$30. Quantity prices apply to 
any combination of titles 
ordered. 


(F) 


(G) Magazine Binders—Magazines 
fit on individual metal rods. 
Designed to hold approxi- 
mately 12 issues. $6.95 each; 
3 for $19; 6 for $36. Quantity 
prices apply to any combina- 
tion of titles ordered. 


(C 


— 


12-unit cartridge case. 

1314” high x 614” deep x 
414,” wide. Tilted compart- 
ments, labels included. $9.50 
each; 3 for $24.95 


These cases and binders are just what you’ve been looking for to solve 
your storage problems. They’re the ideal solution to keeping your 
records, tapes, and magazines neatly stored and well protected. 


A complete set of matched cases is available for your 12” records, 
cassettes, 8-track cartridges, and 7” tape reels. For magazines, you 
can choose either cases or binders to save your valuable issues and 
keep them well protected. 


All cases and binders are sturdily constructed and covered in a hand- 
some leatherette making them attractive additions to any bookshelf. 


The record and tape cases are elegantly embossed in gold and are 
available in your choice of 3 colors—black, brown, and green—lending 
themselves to the decor of any room. 


Magazine cases and binders are available for virtually all titles 
published. Colors are pre-determined by publishers. Gold transfer foil 
is provided for personalization and identification of issues filed. 


Om ey 


CHARGE YOUR ORDER TO YOUR AMERICAN EXPRESS, VISA, MASTER CHARGE OR DINERS CLUB ACCOUNT. 


ZIFF-DAVIS PUBLISHING CO., P.O. Box 278, Pratt Station, Brooklyn, N.Y. 11205 
Please send the following cases/binders at the prices indicated: 
____60-unit Cassette Cases @ $17.95 each; 3 for $49.95—#60026 
_____30-unit Cassette Cases @ $12.95 each; 3 for $34.95— #60027 
_____12-unit 8-track Cartridge Cases @ $9.50 each; 3 for $24.95— #60030 
_____6-unit 7” Reel Cases @ $6.95 each; 3 for $18.50— #60031 
——— 20-unit 12” Record Cases @ $7.50 each; 3 for $19.95— #60029 
Magazine Cases @ $5.95 each; 3 for $16; 6 for $30 
______ Magazine Binders @ $6.95 each; 3 for $19; 6 for $36 

OUTSIDE U.S.A. ADD $1 PER UNIT ORDERED. 
FOR RECORD AND TAPE CASES ONLY— 
Check color choice for back of case (sides in black only): (| Brown [C] Green [] Black 
FOR MAGAZINE CASES AND BINDERS ONLY BE SURE TO INDICATE MAGAZINE TITLES. 
COLORS ARE PRE-DETERMINED BY PUBLISHERS. 


Oe TO Paige a E 
[] CHARGE: C] American Express 


Acct. # eS 
Master Charge Interbank # 


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[] Visa C] Diners Club 


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“Residents of CA, CO, DC, FL, IL, MA, MI, MO, NY STATE, OH, SC, TN and VT add applicable sales tax. 


THE IDEAL SOLUTION... 


AND MAGAZINES. 


STATEMENT OF OWNERSHIP, MANAGEMENT AND 
CIRCULATION (Required by 39 U.S.C. 3685) 


1. 


10. 


2 


C. 


11 


Title of Publication: Sync 
a. Publication No. 02795701 


. Date of filing: October 1, 1982 


. Frequency of issue: Bimonthly 


a. No. of issues published annually: 6 
b. Annual subscription price: $16.00 


. Location of known office of publication (not print- 


ers). 39 E. Hanover Ave, Morris Plains, New Jersey 
07950 


. Location of the headquarters or general business 


offices of the publishers (not printers): 39 E. 
Hanover Ave, Morris Plains, New Jersey 07950 


. Names and complete addresses of the publisher, 


editor, and managing editor: Publisher, None. Edi- 
tor, None. Managing Editor, Paul Grosjean, 39 E. 
Hanover Avenue, Morris Plains, NJ 07950 


. Owner: Ahl Computing, Inc., 39 E. Hanover Ave, 


Morris Plains, NJ 07950; Ziff-Davis Publishing 
Company, One Park Ave, NY, NY 10016 


. Known bondholders, mortgagees, and other secu- 


rity holders owning or holding 1 percent or more of 
total amount of bonds, mortgages or other securi- 
ties: None. 


Extent and Nature of Circulation 


Average 
No. Copies Actual No. 
Each Copies of 
Issue Single Issue 
During Published 


Preceding Nearest to 
12 Months Filing Date 


. Total no. copies 


printed (net press run) 13,166 19,798 


. Paid Circulation 


1. Sales through deal- 

ers and carriers, 

street vendors, and 

counter sales 676 795 
Mail subscriptions 11,875 17,317 
Total Paid Circulation 12;551 18,112 
(sum of 10B1 and 
10B2) 


. Free distribution by 


mail, carrier, or other 

means samples, compli- 

mentary, and other free 

copies 17 100 


. Total distribution 


(sum of C and D) 18,212 


. Copies not distributed 


1. Office use, left over, 
unaccounted, spoiled 
after printing 598 

2. Returns from news 
agents 


1,586 


0 0 


. Total (sum of E, F1 and 


2—should equal net 


press run shown in A) 13,166 19,798 


. | certify that the statements made by me above are 


correct and complete. 
WILLIAM L. PHILLIPS 
Assistant Treasurer 


Figure 2. Timing Diagram. 


D, A 


fe Zus (mn) 


PD/PGM | 


| 
| 
| 
| 
| 
| | 
| 

| 


| 
| 
| 
| 
| 
iteru" 
| 


| Kofer 148 mono 


p 5Oms i 


| DATA 4 ADpeESss IN | 


a ole 2 ys (Min) 
ex 


| > 
| ENP “WAIT? STATE 


| 

| 
BA 
ee 
| | 
| | Aer SELOND MONO 


| 
K2IOF Mono 
| 


Figure 3. Block Diagram. 


di- Le 74.5139 Ul- 
12745134 
EPRo A: Ob 
WAT D AG E 
JI 


The Block Diagram shows how the basic 
EPROM timing needs are met by the circuit. 
As soon as a Memory Request is made into the 
EPROM, a Wait state is initiated. This holds 
data and addresses on the bus line until 
cleared by the timing loop. The beginning of 


Sinclair 4K Basic. Although not necessary 
since EPROMs come “erased” from the fac- 
tory, it is useful to have or have access to an 
ultraviolet lamp for erasing the EPROM. They 
can be bought new for $70.00, but some can 
be found at flea markets and are sometimes 
known as rock hound lights used to fluoresce 
organic and other materials in rocks. At 
$70.00, it should be noted, however, seven 
fresh EPROMs could be bought. 


Once built, programming proceeds by 


POKEing data into the proper addresses. 
USR is then used if the data was a machine 
language program, or PEEK if the data was a 
table, and also PEEK to check that program- 
ming worked properly. 


What Is an EPROM? 

EPROM stands for Erasable Programmable 
Read Only Memory. An EPROM has some of 
the same characteristics as the ROM in your 
machine that contains the Basic language: 

1) Data may be read from the EPROM once 
an address has been presented to the address 
bus. 


78 


PD/PRG 
TO 
u2- 
7415123 EPROM 


Q 
MONO Z 


Aus Puse 


the 50 ms pulse to the PD/PGM pin is delayed 
2 us (capacitor C2). 2 us (capacitor C6) after 
the 50 ms pulse ends, a 4 us pulse from the 
second mono clears the Wait state and allows 
the computer’s bus lines to operate as normal. 


2) Data is retained when the power is turned 


off, almost forever. : 

There are differences: EPROMs need to be 
programmed a byte at a time; ROMs are made 
in large batches each with the same program 
on them. EPROMs can be erased (for repro- 
gramming) by the use of ultraviolet radiation; 
ROMs can never be erased. In a sense, an 
EPROM is midway betway a ROM and a 
RAM. Typically an EPROM has the same 
gross dimensions as a ROM and the same 
pin-out as a ROM (since the computer uses 
both the same way) but in addition it has a 
little quartz window on top that allows the 
ultraviolet light into the EPROM for erasing. 
Erasing results in all data being lost at all ad- 
dresses. There is no selective erasing. 


How Does an EPROM Work? 

The basic element of the EPROM is a ca- 
pacitor which holds a charge. The estimated 
life time (time constant) of the charge is 7 to 
10 years. Each bit is represented within the 


EPROM by one capacitor. A sensing 


amplifier converts this static charge to a TTL 


level voltage that appears on the data lines as 
either a “1” or “0”. Ultraviolet radiation has 
sufficient energy to dislodge electrons on the 
capacitor surface, and as these photo- 
electrons are generated the capacitor will dis- 
charge and data will be erased. Most 
EPROMs read a discharged capacitor as a 
“1” and acharged capacitor as a “0°”. 25 volts 
are used to charge the 32,768 tiny capaci- 
tors on the chip. A typical ultraviolet lamp 
takes about half an hour to discharge the 
EPROM. Manufacturers advise that a tape 
cover be put over the window to prevent 
accidental erasure. 


How the EPROM Programmer Works 

Looking at the data sheets for the EPROM 
selected, one sees various requirements: 

1) Data and address information must be at 
TTL compatable voltages. 

2) For programming, 25 volts must be 
applied to pin 21 (Vpp). 

3) Data and addresses must be held con- 
stant for 50 milli-seconds. 

4) A certain timing sequence must be car- 
ried out with regards to the activation of the 
programming pin, pin 18 (See Timing Di- 
agram.) l 

1) and 2) are easily met. The Z80 has TTL 
compatable voltage levels and four 6 volt bat- 
teries will provide 25 volts. 3) and 4) are 
harder to meet.. A POKE command only holds 
address and data information on the busses for 
about 550 nanoseconds, almost 100,000 times 
too short for proper EPROM programming. 

The solution is to use the WAIT pin on the 
Z80. When the WAIT pin is active (low volt- 
age) all bus information is held constant until 
the pin voltage goes high again. The circuit 
shown has a one-shot whose time period is set 
to 50 microseconds. The other timing re- 
quirements are taken care of by the circuit as 
well, as explained next. 

When the EPROM is addressed (a proper 
combination of A13, A14, and MRQ, mem- 
ory request) by the Z80, U1 switches the 
internal ROM off (via Og-pin 4) and turns on 
the EPROM (via 1,-pin 5). If J1 is in, a WAIT 
state is started when Op pin 12 of U1 goes low. 
At the same time, pin 13 Ip of U1 goes high 
initiating the 50 millisecond one-shot of U2 
(VRI + R2, C4). Q1 of U2 goes low for 50 
milliseconds as does PGM, pin 18 of U3, 
which then programs the EPROM. 2 mil- 
liseconds after the end of the 50 millisecond 
programming period, the second one-shot of 
U2 (R1, C5) disables the Enable pin, pin 15, of 
U1 thus clearing the WAIT state and allowing 
the computer to process the next instruction. 

The design was such as to use a minimum 
of parts. Certain problems therefore exist 
which can be avoided by being aware of them. 
The main concern is that a PEEK command, 
or USR command into the EPROM when the 
EPROM is in the “program” mode will write 
useless data into the EPROM. Therefore, do 
not PEEK or USR into the EPROM without 
disconnecting the 25 volts (J4 out). 


SYNC Magazine 


et the most from your SINCLAIR 


or Timex Sinclair with these practical books from Sync! 


Getting 
Acquainted 
With Your 
ZX81 
Third Edition 
More than 80 shone 


1e Graphics 
tian Pr in 


by Robert Maunder __ 
Creative Computing Fress 


by Tim Hartnell 


o : Creative Computing Press < ~~ 
The ZX81 Companion Getting Acquainted With The Gateway Guide to t 
by Bob Maunder Your ZX81 ZX81 and ZX80 

The ZX81 Companion follows the same by Tim Hartnell by Mark Charlton 
format as the very popular ZX80 This informative volume for the new The Gateway Guide is a practical pro- 
Companion, and assists the ZX81 or- ZX81 or Timex Sinclair 1000 user con- gramming manual for the beginner that 
Timex Sinclair 1000 user in four appli- tains more than 80 programs to help the furnishes over 70 fully documented pro- 
cations areas: graphics, information reader get the most from his Sinclair grams. The majority of the programs 
retrieval, education and games. This computer. Game programs include have been written for easy conversion 
practical guide contains scores of fully Checkers, Alien Imploders, Blaster- from machine to machine (ZX81 or 
documented short routines plus com- mind, Moon Lander, Breakout, Star Timex Sinclair 1000, 4K ZX80 or 1K 
plete programs and a disassembled ‘Burst and Derby Day. The book also ZX80). The Gateway Guide describes 
listing of the 2X81 ROM Monitor. shows programs for cascading sine each function and statement, illustrates 
“Thoughtfully written, detailed, and waves, plotting graphs and tables, data it with a demonstration routine or pro- 
illustrated with meaningful programs.” sorting, equation solving, plus the use gram, and combines it with previously 
—MUSE of PLOT, SCROLL, PRINT, TAB, PEEK, discussed material to help you under- 
52" x 8", Softbound. #17P $9.95 ($2.00) POKE and much more! stand your computer. 


512" x 8", Softbound. #15Y $9.95 ($2.00) 52" x8", Softbound. #160 $9.95 ($2.00) 
Computers for Kids (Sinclair Edition) by Sally Larsen 


This new edition of Computers for Kids is written specifically to introduce 
children aged 8 to 13 to the ZX81 or Timex Sinclair 1000. The book 
requires no previous knowledge of algebra, variables or computers, and it 
enables a youngster to program a Sinclair in less than an hour. There’s 
also a section for parents and teachers. “Computers for Kids is the best 
material available for introducing students to their new computer.” 

—Donald T. Piele, Professor of Mathematics, 

University of Wisconsin-Parkside. 

8¥2"x11", Softbound. #12S $4.95 ($1.00) 


Also available at your local bookstore or computer store. 


aa eet iat et LEL 


Creative Computing Press Dept. NB3F 39 East Hanover Ave., Morris Plains, NJ 07950 


~ 


I Please send books listed below: CFENCGLOSED 1S i e CA, NJ and NY State residents I 
l add applicable sales tax. 
i O CHARGE MY: O American Express O Visa O MasterCard i 
; Card Nor cre oe ye ee eke. Date i 
i Signature i 
i Print Name l 
Address i 
Postage and handling charges appear City/State/Zip i 
t e orkak a O Check here for FREE Creative Computing Catalog. 7 
| curside U's.A.2cds3.00perode Eor faster service, PHONE TOLL FREE: 800-631-8112 


En 


ba. dies (In NJ only: 201-540-0445) 


If you are familiar with dynamic RAM spe- 
cifications (the type of RAM used in the 
16K-64K expansion units), you will know that 
they specify a maximum refresh period usu- 
ally of 2 milliseconds. During a WAIT cycle 
there is no refreshing. So if the data sheets are 
to be believed, dynamic RAMs should not 
work with this EPROMer. However, I have 
found that dynamic RAMs can tolerate as 
much as one or two seconds without refresh 
and without loss of data. I have used my 
EPROM programmer with 16K and the newer 
64K dynamic RAMs and have had no trou- 
bles. If you run into trouble, disconnect the 
dynamic RAMs and use the itnernal static 
RAMs, which need no refresh. 


Making It 

The construction method described here is 
the one I used and may not be best for you. 

What I usually do is lay out the ICs (or IC 
sockets) on a board, making sure that there is 
enough room for miscellaneous components 
and that the wiring which will interface with 
the computer is conveniently close to the edge 
of the board. I seek to minimize runs, espe- 
cially power runs (5 and 25 volt). I then put in 
the other components and use the leads as 
much as possible to wire the circuit. Every 
step of the way I check and double check that 
my wiring corresponds to the schematic. ICs 
get confusing since you must look at them 
from the top and the bottom. (See schematic. ) 

Many years ago I got a lot of color-coded 
telephone wire (what more could I want?) 
from an abandoned factory in my home town. 


Program 1. 
1@ FOR L=@ Fa ase 


20 POKE i16e8002,0@ 
329 NEXT L 


Program 2. 
1a FOR L=8 Fa igi 
. £42288) «255: THEN 
{L+2228S? 


Program 3. 


S IF XINKEYS$<>"P" THEN GOTO S 
16 POKE 16383.85 
20 SAVE “P" 

S@ GOTQ 2a 


Program 4. 
SAME AS PROGRAM 2 


———e_=_=s< eo 


Program 5. 


S IF NOT INKEYS="P" THEN GOTO 


10 POKE M,N1i 

2@ PORE M41,N2 

39 POKE M+#2,N3 

> (REST OF MACHINE LANGUAGE 
` PROGRAM? 


4 SAVE “P" 
249106 GOTO 1000 


Note: M = first address at which the 
data is to be put. N1, etc. is the data. 


80 


I use that to wire the rest of the circuit. I 
recheck the circuit against the schematic and 
then solder all the points. After that I use a 
Volt-Ohm Meter to test the continuity of each 
run as well as that two runs have not acci- 
dently shorted. Good, clean, logical construc- 
tion habits save hours of needless trouble 
shooting later. I try to document what and 
how I have wired it after I am done. 

So now you have a board wired as in the 
schematic. Next it must be interfaced with the 
computer. Here again I used a method which 
may not be right for you. Any method is ac- 
ceptable, including hardwiring it with color 
coded telephone wire. However, this could 
limit future expansion. AP Products (as 
shown on page 42 of the 1982 Jameco Cata- 


log) has jumper headers and cable assemblies 
which can be used. I used two straight double 
row, 40 post jumper headers. One set I sol- 
dered onto the EPROM board. The other set I 
soldered onto the computer’s edge connector 
lower forty. 

I then interconnected the two boards with a 
6” AP flat ribbon cable. Long runs of data 
lines can cause problems and should be 
avoided. Of the four remaining edge connec- 
tor positions, only two are needed: D7 and 5 + 
volts. These I hard wired with a connector in 
between for disconnecting. 

The EPROM is a MOS device and is sus- 
ceptible to damage due to static discharge. I 
have not been overly cautious, yet I have never 
had trouble with static charge destroying a 


Figure 4. Parts List. 


Part. Radio Shack Number. 

(If more than one of item 
in package, then number is 
listed only the number of 
times needed. 

ICs 

Ul 74LS139 ** (See below) 

U2 74Ls123 ee 

U3 TMS 2532, 450 ns. ths 
Resistors 

Rl 10K 271-034 

R2 100K 271-045 

R3 1.8K 271-1324 

R4 1.8K 

R5 1.8K 

R6 3.3, 4 watt (optional) 271-028 
Capacitors 

Cl ~L mfd 272-1069 

C2 -005 mfd 272-130 

C3 .l mfd 

C4 l mfd 272-1419 

c5 470 pfd 272-125 

C6 .005 mfd 

CF 33-mfid; 16V; 272-1426 
Diodes 

DI Diode 276-1101 

D2 Diode 

D3 LED (optional) Various available 
Variable Resistors 

VR1 25K 
Miscellaneous 

Ji,-JA Jumpers or one way switches Any suitable 

J2-3, 3-post jumper or 2-way switch Any suitable 

PC Board 276-153 

IC socket for U3 - 24 pin* 276-1989 


Batteries (4) 
Connector Cable. 


- 6 volt lantern 
(See article "Making It") 


Eveready 509 or equal 


* The other IC's can be soldered into place without too much 


fear of damage or having to replace them. 


But the EPROM, 


and any MOS device, really should be in a socket. 


¥* Available through many mail order houses, 
Active Electronics, JDR Microdevices, etc., 


such as Jameco, 
Addresses and 


prices can be found in the back of most hobby electronics 


magazines. 


ee ee 


SYNC Magazine 


LEARN TO SPEAK 


Logo is the computer language that's sweeping 
the country with its simple, “turtle geometry” 
way of learning computer literacy. And Logo: 
An Introduction is the new, easy-to-understand 
beginner's guide that makes learning and 
using Logo fun! 

Written in simple language and set in big, 
easy-to-read type, Logo: An Introduction is 
specifically designed to be used by teachers 
and students who have little or no knowledge of 
Logo or computers. 

Logo: An Introduction helps computer 
novices with: 

A Creating simple shapes with the turtle 
and combining them to make more com- 
plex geometric forms 

A Learning about “soft” and “hard” saves 


(temporary and permanent computer 
memory) 


For teachers, students and other computer users 
new to the philosophy and methodology of Logo 


an introduction 


j. dale burnett 


NEW _FroM THE PUBLISHERS OF 


CREATIVE COMPUTING 
e Only $7.95! 
è Large, easy-to-handle 11” x 8%” format. 
e Written by a professional educator. 
e Full of illustrations, examples, hints and tips, 
suggesions and explanatory notes. 


For faster service, PHONE TOLL FREE: 800-631-8112. 


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Also available at your local 
bookstore or computer store. 


A Playing with symmetry and curves 


A Learning about arithmetic, logic and Car- 
tesian coordinates 

A Using the idea of recursion—making a 
simple command repeat itself to perform 
more complex functions : 

A Experimenting with words and sentences 

—and more! 

Logo: An Introduction doesn't bog you 
down or scare your students with complex 
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.ended, exploratory style that captures the flex- 


ible spirit and freedom of Logo. 

Use Logo: An Introduction as a supple- 
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potential of this powerful language, and as a 
treasurehouse of suggestions for experiments 
with Logo. Logo: An Introduction is one book 
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enter the exciting world of Logo! 


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MOS device. One should, however, make sure 


Program 6. A Machine Language Program to be POKEd into the EPROM. 


the patterns for Ag at the edge connector 
should be the same as Ag at the EPROM. 


COSMONICS 


FOR THE ZX81 AND TS1000 COMPUTERS 


TIRED OF SAVING 16K 


OF PROGRAM JUST TO SAVE 


2K OF DATA? 


22 222 re 


The COSMONICS READ/WRITE UTILITY will allow you to save 
ONLY what you want to save---from strings, arrays, or a 
location in memory---onto a cassette. You can read it 
back when you want to use it. This data can be used by 
the same program or by different programs. 


The COSMONICS READ/WRITE UTILITY can also make it easi- 
er for you to translate programs which are written for 
other computers in BASIC, and which have "WRITE to cas- 
sette" and ''READ to cassette" statements. This use of 
the utility can greatly increase the amount of software 
available to you. 


The COSMONICS READ/WRITE UTILITY is easy to use, and it 
loads easily. The instructions are clearly written, and 
a short sample program which demonstrates it's use is 
is included. The routine occupies approximately 500 
bytes, and requires a minimum of 2K RAM. 


The COSMONICS READ/WRITE UTILITY is now available for 
$17.00 + $1.50 postage and handling. Calif. residents, 
please add 6% or 6.5% sales TAX. 


Send self-addressed, stamped envelope for FREE catalog. 


COSMONICS 


P.O. Box 10358, San Jose, CA. 95157 


before handling the EPROM that you are dis- LD HL (E-file) ; Load HL with E-file location the end 
charged to the ground of the computer board. of the variables list. A string must 
Do not place EPROM into socket until both EX HL.DE be at the end of that list. 
the timing and the 25v circuit have been LD H, B sClear HL for addition 
checked out. BP a B 
In making the EPROM programmer I ran NEXT: Ẹ 
into difficulties. The main one was that the = pan IAI E rS a eee ee 
EPROM pin (address 7) was defective and JRC -NEXT sIf not check next byte 
only one half of the memory was addressable. AGAIN: TY Pa Pia 
. . . . Ld 
At first I assumed that my circuit was in error. CMP , Øl ;If quote token (#1) then you're done and 
After several days I convinced myself that the RETZ s;you'll return to the BASIC program with 
EPROM was bad and returned it for exchange - + koma span in HL. USR returns HL to the 
and bought another chip as well. The ex- ADD HL ‘Shi t HL four places: 16 times. 
changed chip had the same problem while the ae ae 
new chip appears to be working fine. (I also , ¿Convert letter to number 
é JRC, +ERROR ¿Error if string token less th 
accidently applied 25v to the 5v supply which » 16 ;See if token is arester ther id 
fried 2 RAMS but in the process fortunately JRC +NO ERROR ;If not, jump to NO ERROR 
spared the rest of the computer.) a i net p9 -9 ;ERROR ends IC program with ERROR code "A" 
ý 9 
ADD HL,BC ¿Add converted token to HL 
Trouble Shooting Before Putting the JR AGAIN ;Do again 
EPROM In 
In SYNC (2:1) I showed a method of 
monitoring computer activities by injecting Decimal listing for Program 6. 
signals into the video output. This method is 
useful in dynamically testing the board and 0-42 1-10 2-64 3-235 4-96 
connection to the computer. With the com- 5-104 6-27 7-26 8-254 9-129 
puter on and the board connected, note the e BEN tngo tat Tak eee 
different patterns that the pins on the Z80 20-41 21-214 22-28 23-56 24-4 
make relevant to the EPROM. For instance, 25-254 26-16 27-56 28-2 29-207 
30-9 31-79 32-9 33-24 34-233 


ZX 80/81 8K/16K 


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“FLIP-FLOP”? an interesting combination of 
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5 levels of play 
“ZX-Black Hole” 
‘“ZX-Concentration 
+$1.50 p&h. Florida resident +5% tax 


SYNC Magazine 


Chart 2. Memory Locations. 


POKEing | | 
Address: | ‘bar RAM 


| 


16384 iak 


4K EPROM 


Redundant EPROM 
addresses 


Top 8K BASIC 


Top 4K BASIC. 


The microprocessor starts at zero and 
proceeds up in addresses, doing each 
instruction in turn until it eventually loops 
back to a lower address. 


- CLEVA computer ware 


ENTERTAINMENT PROGRAMS 


ORDER # 


CK161 SNAKEBITE 


BATTLE 
to4p 


STARSHIP TROJAN Pit your wits against the dan- 
gers of outer-space and try to 
save your damaged space-craft. 


Face the monsters hiding in the 
underground complex to find 
the treasure and save the Prin- 


PRINCESS OF 
KRAAL 


cess. 
STARTRACK 


FUNGALOIDS 


Eat the snake before it eats you. 
Variable speed. Create your 
own hazards. 


Demanding game of sully 
nr gs h that can be played by 1 
ayers. 


hoton torpedo 
off the highly 


Use graphic 
attacks to ki 
mobile Klingons. 


Save civilization by bombing 


Repeat for Ag to Ajj and Do to D7 as well. 
Make sure that there are five volts where there 
should be on the board. If all looks good, then 
you are ready to check the timing circuit. 
Program 1 will allow you to set VR1 for 
timing the one-shot. First, put the pro- 
grammer into the test mode (see Chart 1). 
Then run the program. It should take as close 
to 20 seconds to run as you can measure. Ad- 
just VR1 until the program takes 20 seconds. 
If you cannot adjust the programmer to 20 
seconds, then R may be changed, lower value 
to make it faster, higher value to slow it down. 


Applying the 25 Volts 

The 8K user should read the next section 
before going further. 

Since the 25v can be so damaging, triple 
check that the 25v line only runs to pin 21 of 
the EPROM and that the diode is in properly 
and works properly. Then turn the power off. 

Put the EPROM in, turn the power back on, 
and RUN Program 2. If Program 2 ran badly, 
go back and check the wiring. If it ran okay, 
then RUN Program 3. (4K ROM apply 25v 
before RUNning the program; 8K ROM, dur- 
ing the run.) After the program is over and the 
25v are removed, run Program 4. Program 4 
checks to see that your wiring has not created 
redundant addressing in the memory. If the 
program prints more than one address, then 
most likely an address line is open (or the 


EPROM has a defective address pin), and you 
must go back to the previous section and 
dynamically check the address and data lines. 
If program ran okay, then you are ready to 
program the EPROM with real data. 

Verify that when the 25v are connected to 
the Vpp that only 3 to 30 ma are drawn by that 
pin. Also, if some other 25v source is used, 
make sure it is well regulated to within + 1v of 
25v. 


Programming the EPROM 

Programming is simple. Put the Eprom 
programmer into the program mode (Chart 1) 
and then POKE data into the EPROM ad- 
dresses. Because of the way the 8K ROM uses 
the Refresh cycle, I have had trouble on occa- 
sion while the video is on. Therefore, for the 
8K ROM the video must be “off” while the 
EPROM programmer is in the program mode. 
Program 5 is used for the 8K ROM. Do not 
have the 25v on when the 8K ROM video is 


—— Program 7. Entering Hexadecimal Data. 


$ 
5@ POKE L+4+M,USR N 
6@ NEXT L 


Note: M = first address to which data is 
to be POKEd. N = address of Program 6 
in the EPROM. This program cannot be 
used to POKE into the EPROM. 


TS1000 


MACHINE LANGUAGE PROGRAMS 


CK165 ASSEMBLER 
2 pass assembler written especially for the ZX81/ 


TS1000 (16K). It is simply the best assembler avail- 


able for those who wis 
machine code programs. It is designed to run 
alone, or together with the dis-assembler, and/or 
the de-bugging program. These provide a system 
for writing, editing, checking and testing machine 
code programs that is second to none. 
DIS-ASSEMBLER $9.95 
Allows you to read the ZX81/TS1000 ROM (16K 
with the best dis-assembler program available. It is 
written specifically for Sinclair/Timex computers, 


to write their own 


and unlike some programs modified from Intel 
8080 dis-assemblers it gives full Z80 Mnemonics. 


the ever-multiplying fungus. 


Beware—it fights back. 


CRAZY-CARDS 


CUBE 


Learning the rules does not 
seem to help. Totally addictive 
for cheats. 


Use your computer to solve the 


Name 
Address 


mysteries of the Rubik Cube. City 


TWO GAMES FOR THE PRICE OF ONE (ONLY $9.95) 


All PROGRAMS 16K 


January/February 1983 


DE-BUGGER 
Makes writing machine code programs easier. 
Works entirely in decimal. Therefore hexadecimal 
is not needed. (16K) 


Mail To: CLEVA Computer Ware 
P.O. Box 2736 


$9.95 


Please send check or money order. NO CASH! 
New York Residents only add 81⁄4% Sales Tax. 


SHIPPING AND HANDLING 
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83 


on, or else bad data may be written into the 
EPROM. Line 5 of the program is a loop 
which waits for the “P” key to be pressed. 
While the program is waiting, you must set the 
EPROM programmer to the “program” 
mode. Then press “P” and the program will 


POKE the data into the EPROM. You will LD HL, (VARS) 


know that the programming is done when the 

Screen Starts to gitter with garbage as the pro- 

gram gets SAVEd in line 1000. Now place the INC HL 
EPROMer into the “read” mode. Then press LD A, (HL) 
BREAK. LD B, A 


Two sample programs are shown which fobs A 


work for the 4K Basic. One converts a LD HL, (E-file) 


hexidecimal string into a number (Program 
6). The other program converts a number into 
a hexidecimal representation which can be 
PRINTed (Program 8). Programs 7 and 9 DEC HL 


show their uses in Basic programs. DEC HL 
| DEC HL 
Putting It to Work LD (HL), A 
This construction project is really an open DEC HL 
LD B; A 


ended affair, just as computers are. Once AND A,FØ h 

operating, your limits are your imagination, RR 

patience, and money. Though not particularly RR 

difficult to build, like all projects it will take RR 

fortitude to keep on going when things look RR 

hopeless (and they will). 
Published programs should be checked to LD(HL} » A 

see if any changes must be made when relocat- ities , DØDD 

ing them to the EPROM addresses. Relative 

jumps and calls to inside the program have to 

be changed. An example of one particular 

problem is illustrated by trying to adapt the 


Program 8. A Machine Language Program to be POKEd into the EPROM. 


sLoad HL with location of first Variable. 
¿Variable must be there from BASIC 
;program and must be a one letter name. 
¿Get past variable name. 


;Mask last four bits 

¿Convert to number token 

;Load HL with the address of the end of 
;the variable list. A two character 
;string must be there from the BASIC 
program. 


;Move past quote in string to 

;last charactor in string 

;Load converted token into string 

;Move pointer to first charactor in string. 
¿Get rest of number. 

;Mask upper four bits. 


¿Shift upper bits into lower bits 


¿Convert to number token. 

;Place in upper charactor of string. 

;Clear HL just for neatness' sake. 

;Return to BASIC with the last string 

¿being a hexidecimal representation 

sof the number in the first variable. 

;Note: Only numbers Ø to 255 are converted. 


INCREASE YOUR 
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84 


Z-80 
SOFTWARE 
NOTEBOOK 


A must for anyone wishing to program the ZX-80/81 or TS 
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SYNC Magazine 


“Scroll” routine of Logan (SYNC 1:4). The 
routine requires three bytes of RAM, one to 
pass the “Leave” parameter, the other two for 
an internal program register. The addresses of 
the RAM bytes were immediately before the 
subroutine. Obviously, an EPROM can not be 
used for RAM. My solution was to pass the 
“Leave” parameter through the RANDOM- 
ISE command and use the Syntax pointer lo- 
cation for the INTERNAL PROGRAM regis- 
ter since no Syntax pointing is required during 
the subroutine. 

There have been many good subroutines in 
SYNC and the general techniques outlined in 
such articles can be used as long as they are 
not used blindly but understood and modified 
as needed. A good book on Z80 machine lan- 
guage programming will help a great deal. 

A log of the addresses should be kept so that 
you know where what is and that you do not 
over write onto existing programs. Also tape 
copies of all programs should be kept in case it 
becomes necessary to reprogram the whole 
EPROM. 


I have run my programmer with the power 
supply provided with the computer. However, 
when I started to add other devices, it quickly 
became necessary to supplement the power 
supply. If your system is already taxing the 
power supply, you will have to consider ex- 
panding it. 


Construction Outline 

1) Gather parts into one place and fit them 
into the PC board. Use the IC socket for the 
EPROM. 

2) Solder the circuit together. 

3) Test the board for proper connections. 

4) Check and adjust the timing resistor. 
Check the 25v line. 

5) Place the EPROM in and test it with the 
various programs (2 through 4). 

6) If it is okay, program in some simple 
routines and see if they work. 


References 
The MOS Memory Data Book, Texas In- 
struments, 1980. 


Decimal listing for Program 8. 


NEC Microcomputers 1981 Catalog. (For 
Z80 timing data.) 

The Art of Electronics, Horowitz and Hill 
(A good book on electronics in general.) 

*Microprocessor Interfacing Techniques, 
Zaks and Lesea. (A bit dated, especially on 
LSI support ICs, but good on timeless things 
like the S-100 Bus, basics, etc.) 

*How to Program the Z-80, Zaks. (A stan- 
dard book on Machine language program- 
ming the Z80.) 

*Recommended for working with this proj- 


ect. . a 


Program 9. Display of Data 
as Hexadecimal Numbers. 


Note: Line 5 reserves the first variable in 
the variable list for the subroutine. This 
must be done before the FOR command 
sets up its variable. The FOR variable 
cannot be used for the first variable, nor 


0-42 1-8 2-64 3-35 4-126 i 

5-71 6-230 7-15 8-198 9-28 can variables with more than one char- 
10-42 11-10 12-64 13-43 14-43 acter in the name. Line 30 makes sure 
15-43 16-119 17-43 18-120 19-230 that there is a two character string at the 
20-240 21-15 22-15 23-15 24-15 end of the variables list. M = first address 
25-198 26-28 27-119 28-33 29-2 of the area to be displayed. N = address 
30-2 31-201 of Program 8 in the EPROM. 

50 PROGRAMS FOR THE NOW AVAILABLE 


TIMEX SINCLAIR 1000 


Book has 50 top quality 2K listings for the 
unexplained machine. Featuring great 
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graphics providing hours of fun for the 
whole family. 


Also available 50 NIFTY PROGRAMS 
FOR YOUR ZX81 same grade programs 
but all in 1K. Hours of fun. 


$9.95 each includes 
postage and handling 


Listings and cassettes available: 
send stamp for free catalogue. 


JENN PRODUCTS 
BOX 246 
HARRISON, ME. 04040 


January/February 1983 


keyboards 


Standard Computer Keyboard Designed 
for ZX81, ZX80, & MicroAce 


e Same switches used on Apple Computers 
e Two shift keys  ¢ 6-inch space bar 


Plans for keyboard conversion with reverse video — 
$5.00 
Keyboard with complete parts and plans — $55.00 
Wired keyboard, complete with plans — $75.00 


Shipping Charge (by UPS) — $5.00 


LE SS ee i a 
SEND CHECK OR MONEY ORDER TO: 
SEND SASE FOR INFO 
Prices Subject To Change 


L.J.H. Enterprises 


P.O. Box 6305. Orange. CA 92667 
(714) 780-1422 Visa & M/C Accepted 


_ Ed.- A WORD OF CAUTION: Any hard- 
_ ware project for your computer must be 
_ approached with extreme caution. SYNC 
_ cannot be responsible for any problem 


_ that may arise from attempting hardware 
_ projects. Obviously, any damage to your 
computer can be costly in time and 


- money. 


nargware tips = = 


Strong KBD Signals Again 


Stephen G. Turner 


The Hardware Tips in SYNC 2:4 
regarding strong signals on KBD 0 to KBD 
4 came at a time when I had some missing 
shifted functions so I decided to try the 
solution. However, I did not want to 
attempt to remove RP3 which would 
probably involve crushing the pack and 
unsoldering the wires one at a time. 
Instead, using the formula 


R1 R2 


R t = 8.6K = ———— 
R1 + R2 

where R1 is the resistor pack value, I 
decided to wire parallel 62K = R2 resis- 
tors on the underside of the board as 
shown in Figure 1. 

All of my keyboard functions now 
work. So Herb Hornung has a right 
answer. 

A further aspect of the problem 
involves the RP3 itself. Through corre- 
spondence with Sinclair, I found that the 
RP3 may be installed backwards. This 
would cause 20K instead of 10K to be at 
four of the five keyboard connectors. This 


Stephen G. Turner, 6438 S.E. Division St., 
Portland, OR 97206. 


would cause many of the upper case func- 
tions not to work. The correct orientation 
of the RP3 pack is with the lettering away 
from the keyboard connectors. 

You can solve this problem in either of 
two ways. 1) Remove the RP3 and install 
a new one in the correct direction (with 
the lettering away from the connectors). 
2) Use the underside of the board to 
parallel the four positions of high resis- 
tance with 20K resistors. See Figure 2. 

I also learned that the incorrect installa- 
tion of the RP1 (the correct orientation is 
with the lettering toward the Z80A) will 
cause the 16K RAM pack not to work. 
This is the same case only with RP1 
installed backwards. 


Figure 2. 


Incorrect RP3 mounted 


0 1 
KBD 0 to KBD 4 


Bypass Fix (so as not to remove RP3). 


Overheating Problems 


Stephen G. Turner 


My ZX81 with 16K RAM suffers the 
heating problems typical of this combina- 
tion: disappearing cursor, total crash (loss 
of video), “wait state” (keyboard will not 
respond); and blurry display. Generally, 
at any of these states, the 7805 heat sink 
could toast muffins. 

My solution was to remove the 7805IC 
and to mount it externally on a chassis 
box with a 1000uF, 35wvdc cap on the 
input side to clear up the screen inter- 
ference. I used #22 wires from the chassis 
box through the ZX81 grill holes to the 
IC connecting points. This solved the 
problems. 

Users of the Sinclair will have to be 
realistic that overheating is a culprit of 
system failures. Since the Sinclair is a 
tremendous unit for the price, it is worth 
fixing the heating problem. 


Figure 1. Underside of Board 1000 uF 
Sinclair ZX81 
KBD 0 to KBD 4 ye 35wvdc 
Underside aE AEE 
ZX81 board O S5Syde whe 
Sleeve > Ni ar a 
nas 0 K tbe -~ Insulated yp 20KQ 
BU pee here 
Wrap in | ee = 1/4 watt 
P i i resistors 
electrical , „82K resistors, 
insulation! 1/4 watt, 5% Pane ar and 7805IC : ; 
PT i ‘+ Tape sleeve wires with #22 wire 


-- á- - == «= - mew m ow we ee l l 


through bottom 


spaghetti tubing 


86 SYNC Magazine 


RAM Expansion Problems 
Tom Keeney 


ZX80 owners attempting to upgrade 
their computer memory past address loca- 
tion 32767 may have display problems 
unless they make a circuit modification. 
The problem becomes apparent when 
RAMTOP is moved past the 32K bound- =§£_——_______________ Faure 1. 
ary and will manifest itself by the presence m p na 
of black dots in the screen margins. Those aeseriee 
who have installed MicroAce Video 
Upgrades will get a special treat: the dots 
will actually move across the margins in 
an orderly fashion, like a drill team of 
ants! This will happen anytime a key is 
pressed or during any computation. 

The problem is caused by the fact that 
the contents of the data bus are some- 
times shifted into the video when 
addresses above 32767 are accessed. 

The cure is to add the M1 (instruction 
fetch) condition to the video shift signal 
generation logic. As indicated in Figure 
1, this is done by cutting the board trace 
between IC5 pin 8 and [C16 pin 6 and 
installing a jumper between IC5 pin 8 and 
IC17 pin 8. Care should be exercised in 
making the board cut because it is easy to 
accidentally cut the connection between 
IC16 and IC17. | 


Tom Keeney, 9629 Dortmund Dr., Huntsville, AL 
35803. 


USER FRIENDLY SOFTWARE 
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Screen prompted data collection sys- 


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City Bomb (M ‘code - 1K) 

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Snake (Basic 16K) 

Sweet Tooth (Basic & M/code - 16K) 
Slalom (Basic 16K) 

Black Holes (Basic 16K) 


ALL ON ONE CASSETTE FOR 


An Essential addition to your 16K RAM ZX81 


TOOLKIT (written by Paul Holmes) 


Provides the following additional facilities:- 


Line renumber - you state starting number and increment 
value. 

GOTO's and GOSUB’s included in line renumber. 

Search and List - Searches for and lists every line 
containing specified character. 

Search and replace - changes every occurance of a 
character as you require. 


Free space - tells you how many free bytes you have left. 


tem with formula fields and both form 
and spread and sheet display 


ONLY $9.90 (£4.95) 
SPECIAL GRAPHICS ROUTINES 
Ga BATTLESHIPS & ee ers mode -graphics never seen on a ZX81 


Finance—Manager (FM)* | 
Combines budgeting, record keeping, 
and check reconcilement 


operation 
Program—Manager (PM)* 


into one 


CRUISERS GAME 


(16K - 2X81) 

First computer version of this popular 
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position of your fleet then locate and 
destroy the computer's fleet. Visual 
display shows hits and misses made 
and gives running score. 


ONLY $9.90 (£4.95) 


Fill - fills your screen instantly with your speci‘.ed character. 
Reverse - changes each character on your screen to its 
inverse video 

TAPE ROUTINE - provides a system WAIT condition 
until a signal is received in the cassette ear jack. 


All these routines are written in machine code and together 
take up only 1K of your precious RAM - an incredible 
achievement!! 


FOR 16K ONLY $9.90 (£4.95) 


BASIC and machine code program 
monitor and utility Functions include: 
renumber, copy, delete, search, dump, 


( th i 
X GRAPHICS TOOLKIT 6 PauiHomes (ZX81- 16K RAM ONLY) 


22 exciting MACHINE CODE routines that'give you control over your screen as never before! 
Draw/Undraw draws or deletes your multi- Onscreen/Offscreen turns your screen on or off. 


character shape which is defined in a REM Background On/ Off Fills your screen by your 
statement. You may define as many different specified character. When foreground is on existing 


Hex load, Hex Debug, and a condense 
shapes as you like and draw or undraw each at will f nate ff dand sh ill t 
mode that reduces program memory at whichever screen position you choose. Tene In Ut OF rock bebe roca. AASIAN I: 


size Foreground On/ Off use this to ‘protect’ existing Search and Replace will search the screen for 

: characters on your screen. When on new shapes every occurrence of the character you specify and 
will appear to slide behind and re-emerge from replace it with your new character. 

Sais reesvies Square draws a square or rectangle from your 
Border/Unborder Draws a border round the edges specified co-ordinates. 

of your screen area. Edit lines can be used if required. 

Your border is protected when foreground is on. All these routines are in machine code for SUPER- 
Fill Fills any number of lines you specify, starting at_ FAST response! Simply load GRAPHICS 

any line you specify, by your chosen character. TOOLKIT, which repositions itself at the end of 
your RAN, and then your own program (or key ina 
new one), GRAPHICS TOOLKIT uses only 2K of 
your RAM and that includes space to load the 
programmers TOOLKIT described above. 


ALL FOR ONLY $11.90 (£5.95) 


This includes a cassette with 2 copies of the 


All programs are supplied on cassette with full 
size instructions that are easy to read and easy 
to understand. 16K required 

$14.95 each postage included 

VISA MASTERCARD or check 


TOLL FREE ORDERS 

ay i fad i ; 

TE O Aa UPSCROLL DOWNSCROLL RIGHTSCROLL, Esa conpreneneintcton Dott M 
operator #520 ideam code indicated . 


PLEASE NOTE: ALL PRICES ARE FULLY INCLUSIVE AND ARE APPLICABLE FOR EXPORT, INCLUDING AIRMAIL POSTAGE 


PAYMENT MAY BE MADE IN STERLING (MONEY ORDER AVAILABLE AT YOUR BANK) OR ¥OuE OMNES CHEQUE 
MADE PAYABLE TO JRS SOFTWARE DESPATCH NORMALLY 7 DAYS FROM RECE! 
COMPUTER ASSISTANCE INCORPORATED , 
PO BOX 3402 CINCINNATI OHIO 45201 / (513) 381-8778 


19 WAYSIDE AVENUE, WORTHING, SUSSEX. BN13 3JU Telephone: (0903) 65691 


January/February 1983 87 


Reverse Converts all characters to their inverse 
video, control as in FILL. 


Print Position Controls 

UP, DOWN, LEFT, RIGHT - alter your next PRINT 
position in the direétion indicated 

Editprint Moves next PRINT position to first edit line. 


Scroll facilities 


ıı SSU oo 


The “Resources” column lists new 
products for Sinclair users. Suppliers and 


users are invited to send brief product - 


descriptions and details for ordering to: 
Resources, SYNC, 39 E. Hanover Ave., 
Morris Plains, NJ 07950. 


User Groups 


e ZX EXCHANGE. Offers opportunities for 
informal postal contact with other users in 
U.K. and abroad. Full details and a copy of 
the current ZX Broadsheet. Self-addressed 
envelope and two international reply 
coupons to: 

Nick Godwin 
4 Hurkur Crescent 
Eyemouth, Berwickshire TD14 5AP 
United Kingdom 
Virginia 
e Central VA User Group. Contact: 
J. C. McCormick 
PO Box 29177 
Richmond, VA 23229 


User Groups Forming 


Georgia 
e Metro-Atlanta area ZX users. Contact: 
Jeff Feinsmith 
1640 Bethaven Rd. 
Riverdale, GA 30296 
(404) 997-0204 
Virginia 
e Rockingham, Augusta County, area users. 
Contact: 
Andrew J. Milligan 
314 N. Main St. 
Bridgewater, VA 22812 
(703) 828-2623 (bus) 
(703) 828-2469 (home) 


e Tidewater area users. Contact: 
Michael B. Williams 
1300 DePaul Way 
Virginia Beach, VA 23464 
(804) 420-3308 (after 3 p.m.) 


Hardware Improvements 


e End edge connector tarnish problems by 
electroplating the fingers with 24 karat gold. 
$5 plus $3 s&h. For details write: 

Matthew Zenkar 
142 Holcroft Rd. 
Rochester, NY 14612 


Business/Household 
Programs 


e Home Clock Family Bulletins Program. 


Both a clock and bulletin board; clock fea- 
tures menu for clock control; clock displays 
time in large numerals; continuous display 
of bulletins with large text alarm display 
area; and more. 8K ROM; 16K RAM. Cas- 
sette and documentation: $20. Full details 
available. 

King Software 

85 Myrtle St. 

Lowell, MA 01850 


ZX81 


book (120 Pages). 


1K and 16K Programs. 
Games and Application. 
RAM and I/O Circuits. 
Programming Hints 
ROM Routines. 


eck 


NP ee ee ee I NE Rn ene ee r ee eR A TO ee ee ae ae ene an ae ae an en ee ee ee 


œ 
(0 0) 


THE EXPLORER’S 
GUIDE TO THE 


If you have ZX81 then you need this 


Check/M.O. 


$11 from: 
TIME DATA 
3 - Waldon Road 
Califon, N.J. 07830 
Enclosed 
Name 
Address 


ZX-FORTH 


Now you can have the SPEED and POWER of comput- 
ers costing hundreds or even thousands of dollars more 
inside your ZX81. FORTH is now available on cassette 
for the 16K ZX81/TS1000. EASIER to learn than BASIC 
and the most powerful language available for the ZX81 
10 TO 20 times FASTER than BASIC and typically uses 
less than HALF the amount of RAM space needed by an 
average BASIC program. Includes extentions for speedy 
graphics handling, as well as basic data handling func- 
tions. Sample programs written in FORTH included at no 
extra charge are: Scratchpad, a simple word processor, 
and Breakforth, an arcade-type game. Also included is a 
complete bibliography and information about fig- 
FORTH, the international FORTH users group. 


Find out why FORTH is gaining worldwide support as the 
state of the software art and have fun learning about 
computers the fast and easy way. 


THE FOURTH DIMENSION 
1451 N. UNION STREET 
MIDDLETOWN, PA 17057 


ZX-FORTH® 16K CASSETTE $34.95 
Add $2.00 shipping and handling. 
Add $7.00 shipping and handling for foreign orders. 


SYNC Magazine 


3 


e ZX Data-Finder. Sets up files for wide varie- 
ty of uses; allows ADD, EDIT, Title search, 
Word search; flexible file size. Listing and 
thorough documentation: $9.95 pp. 

Thomas B. Woods 
PO Box 64 
Jefferson, NH 03583 


e INVZXTROL. Inventory Program. Controls 
up to 200 items; includes description code 
quantity in stock and price; menu driven; 
easily editable for further use of X 
PRINTER; total control on inputs/outputs; 
totally written in Basic; prompts and all the 
instructions are written in SPANISH; up to 
750 items with 64K module. 8K ROM; 16K 
RAM. Program: $20.00. 

Rafael Ceja Beltran 

Emilio Carranza No. 78 

San Pedro Tlaquepaque Jalisco 
45500 Mexico 


e Complete Portfolio Management. Inventory 
and analysis (e.g., profit, loss, yield, dates). 
Market Forecast. 8K ROM; 16K RAM. Cas- 
sette: $9.95 plus $0.50 s&h. 

Teletek Co. 
15 Central Way, Suite 169 
Kirkland, WA 98033 


Budget Program. Tells how much you have 
to spend per pay period (works on any pay 
period length) and how much you have left. 
8K ROM; 16K RAM. 4K ROM; 1K RAM). 
$10.00 pp. Barchart Program. Indexes 28 


vertical bars 20 spaces high. 8K ROM; 1K 
RAM). $5.00 pp. Credit cards not accepted. 
Al Jorgensen 
Box 202, RD 2 
Vergennes, VT. 05491 


e Home Financial Package. Includes Bond 
Investment, IRA Account Planner, and 
Mortgage Analysis. 8K ROM; 1K RAM. 
All listings: $1.00 and SASE. 

Florida Creations 

Dept. P. 

PO Box 16422 

Jacksonville, FL 32245-6422 


e For FM, HAM, and TV antennas. Design 
your own or modify your current antenna to 
optimize the reception in your specific loca- 
tion. 8K ROM. Listing: $2.50; cassette: 
$9.50. 

Huron Communications 
710 S. Silver St. 
Bad Axe, MI 48413 


e Security Service, will custom secure your 
Basic program, put access codes in it, make 
parts of it nonlistable, or even make parts of 
your Basic program noneditable. For more 
information write: 

Mark E. Rogers 
553 Melrose Dr. 
LaPlace, LA 70068 


Graphics 


e Graph-it. Plots user supplied equations on 
polar or rectangular coordinates chosen 
from menu; calculates scales; accepts equa- 
tion as variable rather than program state- 
ment (no re-programming necessary); help 
section sends results to printer; 
3-dimensional graphs also possible; im- 
proves math understanding as well as dis- 
plays data in graphical form. Run-it price: 
$14.95. 

Run-it Software, Inc. 
732 S. Sherman 
Chicago, IL 60605 


Assemblers 


e The ZX81 Disassembler. Allows you to 
browse through the powerful routines in 
Sinclair’s 8K ROM, check your own ma- 
chine language routines by converting them 
to assembly code; converts 252 regular and 
560 extended opcodes to assembler 
mnemonics; no external table lookups re- 
quired; allows you to jump to any point in 
memory at any time. 12K program. Cassette 
and instructions: $9. 

M. Irons 
46 Magic Circle Dr. 
Goshen, NY 10924 


20 


P.O. Box 603 
Hopkins, MN 55434 


PROGRAMS 
20 MANUAL $13.95 EA 


BEST BUY! BOTH $19.95 SET 
SHIPPING AND HANDLING 


STREET 


CITY STATE 


January/February 1983 


TS1000 AND ZX81 OWNERS 
PROGRAMS: $9.95 


BAR CHART, ETCH-A-SCREEN, INTEREST, 
SPELLING, CHECKBOOK. .. AND 15 MORE! 


ONLY 2K OF MEMORY REQ’D! | 


SEND CHECK OR MONEY ORDER 


TO: 
COMPUTHINK, INC. 


'VEGOTA  #TS1000 [0 ZX81 
(CHECK ONE) 16K RAM 
DESCRIPTION 


PROGRAMS 
2 CASSETTE $9.95 EA 


TOTAL (MN RESIDENTS ADD) 
5% SALESTAX) 


SHIPPING LABEL — PLEASE PRINT! 


HIGHSPEED! 


Z X81 


CHALLENGING! 


NEW! Fast Action Game of Skill 


FURIOUS 
ONLY $12.95 


HIGHSCORE! 


Send Check or Money Order for $12.95 
Plus $1.50 for Shipping and Handling to: 
DAEDALUS SOFTWARE 
8442 Cozucroft 
Canoga Park, California 91306 


89 


Repair Service 


e TS1000/ZX81 Assembler/Debugger. Two- 


pass assembler for entire Z80 instruction set e The only Sinclair-authorized service center 


with standard Zilog mnemonics. Source in 
REM statements with labels, symbols, and 
seven pseudo-ops: ORG, DEFB, DEFW, 
DEFS, DEFC, EQU, and END. Displays or 
prints listings; assembles in FAST or SLOW 
mode, up to 1000 lines per minute, with syn- 
tax checking and diagnostics. Debugging 
features include: memory display and mod- 
ification in hexadecimal, breakpoint with 
display of all registers, line renumbering. 
6.5K machine code and Basic. Cassette and 
comprehensive manual: $14.95 pp. ($19.95 
overseas; U.S. funds only). 

Scientific Software 

6 W. 61 Terrace 

Kansas City, MO 64113 


Back Issues of SYNC 
(UK) 


e Back issues of SYNC, volume 1, numbers 1 


through 6, are available in the United King- 
dom for £1.20 from: 

Hazel Gordon 

SYNC Magazine 

27 Andrew Close 

Stoke Golding 

Nuneaton CV13 6EL 


in the U.S. Offers full repair service and 
maintenance contracts covering full service 
and all parts for the Sinclair ZX81 and T/S 
1000 and the ZX Printer. For information 


contact: 
Customer Service Dept. 
MicroSync Services 
162 Marlboro St. 
Keene, NH 03431 


Workshops 


hands-on experience; extensive reference 
materials. For further information and other 
upcoming workshops, write: 

TERC 

8 Eliot St. 

Cambridge, MA 02138 


e Workshop series “Microcomputers in Edu- 
cation.” Tallahassee, FL, Jan. 18-20; Wash- 
ington, D.C., Feb. 7-9; New York, Feb. 
17-19. Designed for professional develop- 
ment of educators at all levels; emphasis on 


For 1X81/TS$1000 with 16K 


KROK 


SCIENCE FICTION 
Games of Bart Trueheart 


Better than Pac-Man. Split-screen, split-second 
timing, action packed adventure. Left portion of 
screen shows your progress through multiple 
levels of a complex maze, pursued by relent- 
less crocodiles; upper right portion of screen shows 
details of each room. Encounters with graphic 
spiders, snakes, bats, monkeys. Find treasure, 
coins, keys, ring, codes, a silver dagger. En- 
gage in kill-or-be-killed struggles. Break code 
and find hidden doors to additional complex 
subterranean adventures. $8.95. 


CRYPTO- 
WHAMMER 


SO1: THE MALTRAXIANS ATTACK 
SO2: RAID ON COLONY ALPHA 


SCIENCE FICTION 
ADVENTURES 
SOA1: DETENTION STATIONINTRAG $13.95 


SOA2: ESCAPE FROM THE DARK aces 
13.95 


FANTASY ADVENTURES 
of Simon Swordwielder 


MSA1: LABYRINTH OF THE jamaica: = 
14.95 


$9.95 
$9.95 


Use this program to solve cryptograms, break 
codes. Displays original code at top of screen, 
changes as code is broken below. Performs 


character counts. $6.95 Part 1 of the adventure of the wandof Kormantu 


MSA2: UNDER THE TEMPLE OF KHARDAM 
$14.95 


Part 2 of the adventure of the wand of Kormantu 
All games are for ZX81/TIMEX 1000 16K RAM 


All games include cassette instructions and pro- 
gram notes. 

Add 10% for postage and handling. 

Send cheque or money order to: 


TURNER, ELCY & COM., 


P.O. Box 395 
Port Huron, Ml 


Brown Coitage Industries 
5486 Bright Hawk Court 
Columbia, Md. 21045 


Dear Friends: 

Please send me O KROK, O CRYPTO-WHAMMER. Please send my order to: 
Name 
Address 

City, State 


CJ | have enclosed a check or money order. 


0 Please charge my VISA or Mastercard (circle) No: 


SYNC Magazine 


Games 


e ZXBOMBER. Includes 11 ranks, 40 cities of 
varying sizes, and a mixture of graphics (for 
the attack) and text (upon return to base). 
8K ROM; 16K RAM. Complete instructions 
included: $6.95 incl s&h. (Coming soon 
DUNJUN, the ultimate adventure game.) 

Blake Kincaid 
3704 S.E. 42nd Ave. 
Portland, OR 97206 


e Masterbrain. Computer invents a fiendish 
code which you must decipher. You are 
given clues as to how close your guess ap- 
proximates the five place code. You will be 
rewarded for doing well and chastised for 
doing poorly. The solution can be called if 
you are having trouble. Program uses 
graphics. 8K ROM; 16K RAM. Cassette: 
$9.95 plus $1.00 s&h. 

David B. Scollin 
350 Laughlin Way 
Redwood Valley, CA 95470 


e Laser Invasion. Exciting arcade game. 8K 
ROM; 2K RAM. Listing and instructions: 
$2.00 plus SASE. 
ZX- Vision 
PO Box 42 
Ringoes, NJ 08551 


e Artificial Flight Program. Fly your private 
plane to the runway and land safely or find 
out why you crashed and try again. Graphics 
real time; three separate displays. 8K ROM; 
16K RAM. Cassette: $5.00 plus $1.00 s&h. 

Greg Keller 
6409 S. Boston 
Fort Smith, AR 72903 


Catalogs/Directories/ 
Product Lists 


e The Sinclair Software Sourcebook. You can 
sell your programs through a listing in 1 of 
8 categories; listing runs for one year for 
$10. Book will be updated and reprinted 
periodically. Write for full details and list- 
ing form. 

Drivers Software Sourcebooks 
PO Box 1048 

Port Hardy, B.C. 

Canada VON 2P0 


¢The Watchmakers Guidebook to the 
TIMEX/Sinclair Computers. Directory of 
suppliers with a brief description of their 
wares; includes about 120 software 
suppliers, 50 hardware, and 20 ancillary; 
directory of user groups, TIMEX/Sinclair 


specific magazines and books, index to ar- 
ticles in general computer magazines on the 
T/S computers. 44 pp. $3.95 plus $1 s&h. 
Quarterly updating planned. 

TSG Enterprises 

Guidebook 

54 Richwood PI. 

Denville, NJ 07834 


e Games and Utilities for the ZX81. Send 
SASE for free program and information to: 
Brown Software 
53 Cliff Ln. 
Levittown, NY 11756 


Tape Accessories 


e L-Monitor. Multi-purpose tape loading aid. 
Features accuracy and reliability of sensitive 
microammeter; compact and attractive; 
plugs in between any computer and recorder 
using standard 1%” connectors; assures 
first-time LOADs; wide sensitivity range, 
user adjustable. Output for earphone, 
amplifier or tape duping. Instructions for 
tape head alignment, hi-fi tonal balance, 
and using your own stereo system to LOAD 
and SAVE programs. Kit: $17.50; assem- 
bled and tested: $23.50. U.S. pp. 

L-Monitor 
819 Kenyon Ln. 
Newark, DE 19711 = 


` 
ll 
Bob Berch’s 
Integer BASIC COMPILER 


—increase your speed 20 plus times! 
—amazing 3K program includes all run 
time routines 


commands/functions 
DIM RAND -256 variables (two letter) 
FOR/NEXT CLS ; 
LET COPY -26 single DIM arrays 
IF/THEN SCROLL 
GOTO AND, OR sorry, no Strings except 
GOSUB/RETURN NOT in PRINT 
PRINT ABS ; 
LPRINT SGN -two versions 
PLOT/UNPLOT USR 16K w/code in 29-32K 
POKE RND 64K w/code in 13-16K 
STOP PEEK 
FAST INKEY$ 
SLOW MOD(* *) 
PAUSE AT & TAB 
$22.00 ppd 
both versions for (cassette) 
NY residents 
add 7% 
Bob Berch 


19 Jaques St. 
Rochester, NY 14620 


January/February 1983 


a Keo 


ZX80/81 USER Beat the Program 
Loading Blues witha — 
DATA CONDITIONER II 


USE THE DATA CONDITIONER II to; 


e Eliminate cable changing 

e Allow accurate volume control setting for 
a perfect load every time. 

e Allow for easy cueing of tapes 

e Allow you to use the remote feature on 
your tape deck. 


Order TODAY by phone using Visa, American 


Express, Master Charge, 24 hour toll FREE 
number 1-800-367-5134 


order part number CSL-DS $49.95 


address: Communication System 
Laboratories 
94-165 Leokane Street 
Waipahu, HI 96797 


allow 3 weeks for delivery 

add $3.50 for shipping & handling (air parcel 
post) 

add $5.00 UPS Blue Label 


SERIOUS PROGRAMMERS 


“MUST-HAVE” UTILITIES 
For ZX-81 and T/S 1000 Computers 


s READ/WRITE Cassette Data Files 
Fast @ Flexible ® Error checking 
($10) Works in 2K RAM 


= SAVE/MERGE/ERASE BASIC 
($15) 


Powerful editing tool 

Merge BASIC programs 

Save BASIC program on data file 
Erase blocks of BASIC 

Use in 16-64K RAM 

(includes read/write data files) 


Simple user interface via USR function 

Well—documented user manuals 

Available on tape cassette in 
relocatable machine language 


SASE for info 
Nz 
Sixt 
irius Ware 


6 Turning Mill Road 
Lexington, MA 02173 


Check or MO delivers now 


2K 2716/2516 EPROM-READ CARD 
CONNECTS DIRECTLY TO THE TIMEX-SINCLAIR 1000 AND THE SIN- 

CLAIR ZX81/MODIFIED ZX80 (INST. SUP). 

EPROM-READ CARD + PRE-PROGRAMMED EPROM $29 (£18). P&P $1.60 

(£1). 

THE EPROM IS PROGRAMMED WITH BREAKOUT, LIFE + TOOLKIT (RE- 

NUMBER (INCLUDING GOSUB/GOTO) READ, DATA, RESTORE, BLOCK- 

FILL (OF SCREEN), BLOCK-DELETE (PART OF PROGRAM), SIZE (OF 

PROGRAM), FREE (MEMORY), HEX-D, D-HEX, M/C LOAD (FAST)). 

PROGRAMS ALL INSTANTLY AVAILABLE ON POWER-UP. NO RAM 

USED. 

EPROM PROGRAMMER AVAILABLE S.A.E. DETAILS. 

ORME ELECTRONICS-2, BARRIPPER RD. CAMBORNE, CORNWALL, 

ENGLAND 


IMPORTED GAME CASSETTES 
TIMEX + ZX81 16K $14.95 EACH 
“10 GREAT GAMES” NEW RELEASE! 
JUST IN TIME FOR CHRISTMAS KIDS 
“TRADER JACK” FANTASTIC FUN GAME 
BUSINESS LOGIC-SOUTH PACIFIC LOCAL 
THIS ONE IS FOR DAD AND MOM! 
SAVAGE SOFTWARE, PO BOX 441 
TITUSVILLE, FL. 32780 


Artificial intelligence 
Telephone Book A1 


This program will store approx. 85 entries, but the 
best thing is that it is an A1 program so you can “Talk” 
to it in English. Suppose you don’t have the name and 
only the address . . . no problem, Suppose you only 
have the number... no problem, etc. on cassette 
(16K) $3.95 + $1.00 postage and handling. ny resi- 
dence add 7% sales tax. 

FROG SOFTWARE COMPANY, pob 95, Gien- 
mont, NY 12077 


PRICE SLASHED FOR 1983 
CUSTOM ATTACHE CASE 


form fit for ZX80/81 TS1000 and hard- 
ware $34.95 plus $3.50 p/h send 
check/money order to: 


COMPUTA-DEK 6009 Kenwood Drive 
Nashville, TN 37215 


PLEASANTREES HAS 
THE PICK OF THE CRO? 
FOR 16K! 


ZXAK - MAN true full-screen arcade version (MC) $12.95 
BOGGIER 2-4 play for cheat-chek, nice graphics $9.95 
BASE CONVERSION great machince language aid $6.95 

5 FUN'N’ GAMES ZXAK-man , states game, 3 others $9.95 
3-D WORM MAZE addictingly frustrating game $9.95 

ZX PROGRAMING FORM PADS (50 Sheets) per pad $2.19 
Post 75¢ ea. pad $1.50 ea. cass. 

PLEASANTREES 7760 N. Hupdawn Tucson, AZ 85741 


Only $10 
Grizzly FLIGHT SIMULATION 
and AIRLINE MANAGEMENT Game 
Free Animated Graphics 
Course with each order! 
Hensley & Associates 
Box 334 Asheboro, NC 27203 


letter from eni 


Stephen Adams 


One of the advantages of living in England, 
Home of Sinclair Research, is that we get to 
try out some of the “extras” before anyone 
else. Here are some of the things that may 
cross the Atlantic from England for the ZX81. 

An exciting new development for the ZX81 
enthusiast is an alternative keyboard to re- 
place the “touch,” but not very sensitive 
keyboard. There have been a lot of complaints 
on this side of the water that the keyboard is 
slow and difficult to use because of the lack of 
“moving keys.” This new “KLICK” key- 
board from Kempston Electronics (60 Adam- 
son Court, Hillgrounds Road, Kempston, 


. Bedford, England) is the same size as the 


Sinclair, but 1 cm taller. The keys are made out 
of proper keyboard switches and have the ap- 
propriate legends stuck on top. The layout of 
the keys is also the same, and there is even 
space for a repeat key. The keys move under 
your fingers, and it is very light and easy to 
use. Connection to the ZX81 is made by plug- 
ging two plastic cables into the keyboard 
sockets instead of the Sinclair keyboard. The 
Sinclair keyboard has to be first removed by 
peeling it back (it is only a few millimetres 
thick) and then after undoing the screws on the 
base removing the keyboard “tails” from the 
sockets. The result is beautiful to look at as 
well, as it is finished in black to match the 
computer. The cost including U.K. VAT at 
15% is £27.20. 

The same firm also has a keyboard beeper 
and repeat key modules which fit inside the 
computer under the keyboard. 

A keyboard beeper that does not require 
any soldering at all is made by Fulcrum Prod- 
ucts (Hillside, Steep lane, Findon, Worthing, 
West Sussex, England). This comprises a 
printed circuit board which is small enough to 
fit inside the ZX81/Timex underneath the 
keyboard or even under the computer’s own 
printed circuit board. The hole connections 
within the computer are made by inserting 
spring clips into the holes which are already 
plated to carry the circuit from one side of the 
board to the other. 

The connections to the keyboard are done 
by removing the keyboard “tail” from the 


Stephen Adams, 1 Leswin Rd., London N16 7NL. 
United Kingdom. 


socket on the computer board (only one has to 
be moved) on to an identical socket on the 
beeper. A keyboard strip containing the same 
sort of metal strips is then plugged into both 
the keyboard socket and the beeper. This is all 
the connection required. It can be easily re- 
moved if the computer has to be sent back for 
repair. 

It beeps whenever a key is pressed includ- 
ing all the modes (G, F, L, and K). It also 
works on all the keys when the SHIFT key is 
held down. It is a very good method of making 
sure that the computer has registered the key 
press on Sinclair’s thin keyboard. The cost of 
the board is £8.95 including VAT. 

While we are on the subject of solderless 
additions, how about a RAM board which fits 
inside the ZX81 via a set of screws (no RAM 
pack wobble here) and can have up to 16K of 
semistatic memory on it? The board is called 
the INCREMENTAL RAM board and is 
made by East London Robotics (Finlandia 
House, 14 Darwell Close, London E6 4BT). 
The board costs £13.23 for the 16K board and 
£4.93 for each extra 2K of memory required 
(one plug-in chip). 

The board uses CMOS 6116 RAM chips 
which can be purchased in the USA. Being 
semistatic CMOS they take less power than 
16K dynamic RAMs and can be powered by 
batteries to keep a program intact when not in 
use. They are also more reliable than dynamic 
RAMs which rely on the REFRESH signal. 
The increment board is easy to fit with brass 
screws through the plated holes on the printed 
circuit board to make the connections. It can 
even be removed with no trace when sending 
the computer back for repair. There is also the 
advantage of not having a wobbling RAM 
pack blocking up the expansion port. 

If, however, you decide later that you want 
to use more memory, the increment RAM can 
be moved to any position in memory to give 
increased Basic memory from 32K upwards 
or from 8K upwards for running machine 
code programs in, etc. 

Another basic problem with the Sinclair/ 
Timex is the amount of glare that you can get 
using an all white screen. Most computers 
work in reverse to the Sinclair and PRINT on a 
black background, thus saving eye strain. 
Now a device is available from D. Fritsh (6 


SYNC Magazine 


land 


Stanton Road, Thelwall Warrington, Chesh- 
ire, England) which will reverse the TV 
screen at the flick of a switch. This inverse 
video module (£7.50) sits on top of the ULA 
chip inside the computer, stuck there by a 
piece of sticky tape. The only connections re- 
quired are to the video lead and to the power 
(+5v and Ov). The switch is already wired up. 

The instructions are superb, and they even 
include a template for drilling the hole for the 
switch. An added bonus is that it improves the 
“crispness” of the display and stops graphics, 
for instance, from looking fuzzy. 

If I seem to be a hardware fiend, it is only 
because the best programs over here are in 
machine code and some of them will not oper- 
ate in the USA without modification. This is 
because they do not use the Sinclair ROM 
routines to put out the TV picture, but write 
their own in order to get fast graphics. The TV 
system over here is 625 lines PAL on the UHF 
band. The USA frequency is VHF NTSC 525 
lines and is totally uncompatible. 

One of the programs in Basic that I have is a 
word processor by Asher & Kuehn (60 St. 
Lenonards Gardens, Heston, Middx, En- 
gland) with two forms called ZTEXT and 
LTEXT. ZTEXT provides only CAPITAL let- 
ters while LTEXT gives both CAPITAL and 
lower case letters on the printer. Both are on 
the same cassette for £6. 

There are two modes: write text T and edit 
text, the second giving all the functions of 
insertion, deletion of lines of text, searching 
for a specified word or phrase, replacing the 
found word with another or printing it out ona 
Sinclair printer. Also it can be used to “mail 
merge” letters by indicating on the standard 
letter where words should be different on each 
letter (Name, Address, etc.). The program 
then stops to allow you to insert these details 
and ENTER will carry on the printing. The 
number of variations of setting the page 
width, number of lines, tab, and other format- 
ting commands are available as a dot followed 
by the code letters. It is very good, given the 
restrictions of a 32 character screen, but does 
not have the ability (in the case of LTEXT) to 
display lower case or all the punctuation 
marks. These are usually indicated by IN- 
VERSE characters on the screen. Altering the 
program to use a real printer can be done. 


January/February 1983 


ww FR D -R A M 


FOR ZX80/81 8K ROM/16K RAM 


Starship Crisis/Planet Quiz...... 


"Starship Crisis" is a suspenseful 
game where knowing the facts about 
the Solar System is all that can 
Save you. 1 player or a group. 


"Planet Quiz" is an educational quiz 
game on our Solar System. Learn while 
having fun. A score is kept for each 
player. 1 to 4 players. 


Minareden Teron wa ee eet an als sd EAA 


Amaze your friends as your computer 
appears to read minds. Two games- 
Matrix and Clock. Confusing fun. 


* All programs are recorded on quality 
cassettes. Prices include handling 
and shipping. 


D-RAM Products 


4352 GROW ROAD, NW 


STANTON, Mi 4asss8a 


ZX-80 8K ROM USERS 


Completely expand your ZX-80 with 
8K Rom to a ZX-81 with full use of Fast 
and Slow. Smooth flicker free per- 
formance! 


Complete Kit: $32.50 & $2.50 postage & 
handling; PCB only $19.95 & $1.25 
p&h; Parts Kit Only $12.55 & $1.25 p&h. 


The Expandable ZX-80 and ZX-81 

A book of hardware projects that you 
can build yourself, from memory ex- 
pansion to speech synthesis. Only 
$9.95 & $1.25 p&h. 


Program writers: We publish software 
and complete books. Write for details. 


COMPUTER ENGINEERING SERVICES 


The Jarrett Company 


P.O. BOX 1222 
SHOW LOW, ARIZONA 85901 


(Dealers Inquiries Invited) 


GLASSWARE 


WE’RE NEW BUT OUR 
GAMES SPARKLE! 


Challenging games for ZX81 on Timex: 


. GOLDMINE—move into the mineshaft, col- 
lecting gold pieces. Blasting away rocks to 
get more, but watch out for cave-ins above! 
Cash in part of your gold for more dynamite. 
Graphics and prompts. Hard to win! reg. 
16K RAM. Cassette & documentation 
$4.95 


. MASTERMINED—ZX/TIMEX version of 
popular logic game, with full display, on- 
screen instructions and prompts. reg. 2K 
RAM. Cassette $2.95 


Both for $6.95 


We have more if you like these. 48 hour 
shipment on M.O., cert. check. add 75¢ ship- 
ping and handling. 


GLASSWARE - D. GLASS 
Rt.14 Box 369 
Johnson City, TN 37615 


WORD PROCESSING 
For ZX81/Timex 1000 with 
16K 32K 48K or 64K RAM. 


(Please specifiy RAM version.) 
ONLY $7.95 (Limited time only). 


ALSO AVAILABLE: 


Checkbook Balancer—helps_ with the 


monthly chore! Anamur—are you able to be 


King? Rule an island to see! Escape— inside 
a deadly barrier with you are Xroids. Can you 
guess who's for dinner? Rebel Raider —Dark 
Faker is coming! You must stop him! Market- 
ing—buy/sell stocks to make your fortune, 
or nothing! SPECIAL: Any one program for 
$7.95 add only $2. for each additional pro- 
gram! 


MARANATHA 
Box 759-C, Mableton, Ga. 30059 


LRSRSRSARSSALAZESAESEARESR EERE SS SE SE 


SIMPLIFY TAX FILING WITH 


AX\NARE 


SCHEDULE: FORM: 
LIST CASS LIST CASS 

A/B 2106 

C 2110 

E 2210 

G 3468 

SE 4255 


| 


HH MG HHH HH HHH HHH HHH HHH HEH HHH 


BUSINESS SOFTWARE 


MORTGAGOR/AMORTIZER 
DEPRECIATION w/ ACRS 
CHECK REGISTER 
CLIENT DATA FILE 


KKK KHEHEHHEEHEHEEHHH EKER KEKHHHHE 


$4.00/LISTING $8.00/CASSETTE 
16K RAM NEEDED 
MAIL CHECK/MONEY ORDER TO: 
T. DUNN 
151 GREENVILLE AVE. 
JERSEY CITY, N.J. 07305 


HHEGRGE AEH HEE HEHEHE HERE AAA 


SANTE FE INDUSTRIES-soon to be the biggest 
name in software/hardware for the Timex/Sinclair 
and Commodore Computers. Will send you (for $3.00 
s & h) software/hardware information on, 16K RAM, 
I/O, Rtty, CW, Satellite antenna pointing, contest log- 
ging, accounting, inventory, classroom, mail list, etc. 
included-over 30 1K ZX/Timex programs, ZX80 to 81 
conversions, error table. SANTA FE 2342 S. Dun- 
dee CT., Highland, MI. 48031 


SIMPLY THE BEST! 


IMPORTED GAME CASSETTES 
ZX81 16K $14.95 EACH 
“TRADER JACK” FANTASTIC FUN GAME. 
BUSINESS LOGIC — SOUTH PACIFIC LOCAL. 
“ZX81 MONOPOLY” UP TO 6 PLAYERS. 
SPECIFY EITHER SPANISH, BRITISH OR 
AMERICAN LANGUAGE VERSION. 
SAVAGE SOFTWARE, PO BOX 441 
TITUSVILLE, FL. 32780 


TAX DEDUCTIBLE 


program package - complete form 1040, 
itemized deductions, 1982 tax tables. 
16K RAM. Send $24.95 ZX1040 Soft- 
ware, 3311 Thomas Dr. Palo Alto, CA 
94393. CA add 612%. 


93 


EEE ETETTTT LLL ——@eo 


For ZX81&TSIOOO I6K RAM 


NEW DOMINO Game 


challenging and exciting 
Other New Games Available 


$ 9.95 p EAER 


send SASE for FREE info: 
PHOTOLAB 
P.O. Box 21124 
Kennedy SpaceCenter, FL. 32815 


“BAC-TRAC” 


16K GAME FOR ZX81-SIMILAR 
TO “PAC-MAN” 


WITH “DOT EATER” AND 
“GHOST TRACKER” 


LISTING— $2 
CASSETTE TAPE — $7.50 


OTHER SOFTWARE 
AVAILABLE 


THE LAMB'S SOFTWARE 
1469 AALBORG WAY 
SOLVANG, CA. 93463 


The Troiano Software Company is now 
offering for the ZX81 a graphics, games, 
accounting, math and utility package 
with 12 programs in all! Only $4.00. 

Troiano Software Company 

PO Box 40 

Nesconset, New York 11767 


Brainchild Computer Works, Inc. 
Microprocessor Design & Development 
Hardware - Software - Peripherals 
Consulting - Contract - Prototypes 

P. O. Box 506 Phone: 
Pewaukee, WI 53072 (414) 691-3903 


Custom Computer Carrying/ 
Storage Cases 

High impact plastic, foam padded. 
Holds computer, memory, cables, and 
recorder. $49.95 
Sights & Sounds Systems 
P.O. Box 29177 
Richmond VA 23229 


HOME INFORMATION CENTER 
FOR SINCLAIR ZX 81 OR TS-1000 
NEW Home Clock & Family Bulletin Board. Runs 
continuously, easy to use, 16 features, MENU 
driven, LARGE clock digits, set date/time/alarm/ 
clock rate, enter & update bulletins. Requires 
16K. Fully documented for end user. $20 com- 

plete or Request FREE Brochure. 
KING SOFTWARE 
85 Myrtle St., Lowell, MA 01850 


Software Review 


QSAVE Peter D. Hoffman 


The QSAVE package consists of: 1) a 
hardware unit, 2) a software program, and 3) 
an instruction booklet. It performs tape 
SAVE, LOAD, and verify at 4000 BAUD. 

The hardware box has two standard phono 
plug connections for feed-through of the 9v 
power supply and two for connecting the re- 
corder output and computer input. Described 
as a filter, a two stage amplifier, and a signal 
shaper, this unit is used only during LOADing 
to condition the signal from the recorder to the 
computer. 

The actual circuit design is simple but eleg- 
ant. A four stage op amp chip is used along 
with a timing chip for voltage doubling. Two 
stages of the amplifier give a mild gain and the 
other two stages are arranged as high and low 
filters. Clipping diodes provide the square 
wave signal shaping. The circuit board and 
overall construction show a quality level of 
wokmanship. The current draw was measured 
at 17ma. 

The software program runs the Basic por- 
tion automatically after LOADing and relo- 
cates the machine code program above 
RAMTOP at address 32000. USR calls access 
the SAVE, LOAD and verify functions. 

The verify function checks on whether the 
program has been saved properly by calculat- 
ing a simple checksum of the bytes and then 
recording this value at the end of the tape. 
During verify the tape is read (but not 
LOADed to memory), the checksum is calcu- 
lated and compared to the checksum recorded 
on the tape. It does not make a byte-by-byte 
comparison with the program still in the com- 
puter, nor does it make any use of the program 
in memory. If the verify does not work, you 
perform the SAVE operation again. 

The QSAVE program must be LOADed 
each time the computer is powered up or re- 
set. This is a nuisance and could interfere with 
other programs using the protected USR area 
above RAMTOP, as more and more programs 
seem to be doing. The QSAVE code could be 
put in an EPROM or nonvolatile memory in 
the 8K-16K address space. 

The program SAVE/LOADSs the entire 16K 
of RAM everytime. This takes 25-30 seconds. 
The program could be made capable of load- 
ing just up to E-LINE as the Sinclair software 
does. Since the SAVE/LOAD actually starts at 


Peter D. Hoffman, 5618 Martinique Dr., Corpus 
Christi, TX 78411. 


address 16301 and goes to 32896, the user 
might have problems with RAM at addresses 
just below 16K and just above 32K. Finally, 
by POKEing in the proper values, the pro- 
gram could save a full 48K of user RAM in 
less than 1% minutes. 

A BREAK key capability would be helpful 
since the program would hang up in the ma- 
chine code during the search for the proper 
recorder volume. 


TO 
SOFTWARE PROFILE 
Name: QSAVE _ 
Type: Tape Facility 
System: 8K ROM; 16K RAM 
Format: Cassette; hardware 


Summary: An inexpensive alternative 
that gives very reasonable 
LOADing times. 

Price: $37.50 _ 

Manufacturer: 


Personal Software Services 
112 Oliver St. 

Coventry CV6 5FE 

United Kingdom 


The software shows some evidence of hav- 
ing been rushed to the market without a final 
cleanup. For instance, the machine code pro- 
gram has some extraneous code that is never 
used. The machine code for LOADing the 
program above RAMTOP appears to test for 
old vs. new ROM and make the necessary 
changes to allow a call to ROM for the FAST 
routine by the old ROM. But, in fact, the old 
ROM capability is not there. The machine 
code also puts the computer in FAST mode 
and then leaves it there. A corresponding 
switch back to the SLOW mode before return- 
ing from the machine code program would be 
useful. 

The key to understanding how this program 
works (and, to an extent, the Sinclair SAVE 
and LOAD procedures) is the fact that the bits 
are represented by the length of the silences on 
the tape. The machine code program listens 
for and measures the length of the silences. 
The tone bursts on the tape are nothing more 
than separators of the silences. This puts a 


SYNC Magazine 


premium on having good quality tape with 
low inherent background noise and a good 
erase head. 

Also similar to the Sinclair tape proce- 
dures, the BAUD rate for the data transfer is 
variable depending on the mix of 0 and 1 bits. 
On the Sinclair the BAUD rate is 5600 if all 0 
bits are being transferred and 3000 if all 1 bits 
are being transferred. Since in QSAVE each 
bit is a single silence separated by tone bursts, 
the apparent audio frequency is the same — 
5600 Hz and 3000 Hz. This is probably push- 
ing the limits of frequency response of inex- 
pensive recorders that are intended for voice 
recording only. The 4000 BAUD is an average 
value only. 

I then performed a series of experiments 
with several recorders and the QSAVE pack- 
age. The first was a bottom-of-the-line GE 
that had been resurrected from the dusty 


depths of a closet and used from the time the. 


computer was purchased. After detuning the 
software program to 2000 BAUD by POKE- 
ing new values into the delay loops, the 
QSAVE package would work with this re- 
corder. This detuning lowers the apparent 
audio frequencies by half. Even so the volume 
setting was very touchy. 

A second recorder of unknown history and 
condition could not be made to work with 
either the original 4000 BAUD version or the 
detuned 2000 BAUD version. 

The third recorder was a nearly new top- 
of-the-line Sony. The QSAVE package 
worked at 4000 BAUD. Furthermore, the vol- 
ume setting was almost irrelevent. Reliable 
LOADing was obtained at any volume setting 
from % to full volume. 

Lastly, another Sony identical to the third 
recorder was tried. It had seen heavy record- 
ing usage and would not even load the stan- 
dard Sinclair tapes. After the worn record/ 
playback head was replaced, it performed as 
well as the new model. 

These experiments suggest that fairly good 
recording equipment is required to use the 
QSAVE package. Since the silences on the 
tape are critical, frequency response and rea- 
sonable signal-to-noise ratio by the playback 
head are needed. None of the recorders had a 
tone control. The instruction booklet indicates 
that a half setting on the tone control can re- 
duce the sensitivity of the volume setting. 

In conclusion, QSAVE is an interesting 
package. It does perform as advertised when 
used with good quality recording equipment, 
but there is room for improvement to a fine 
product. I plan to wire the QSAVE hardware 
into a new computer case (my current project) 
and to put the machine code program in non- 
volatile memory below 16K. Unless and until 
a reasonably priced disk drive is available for 
the ZX81, this package is an inexpensive al- 
ternative that gives very reasonable LOADing 


times compared to the normal Sinclair tape 


operations. 


January/February 1983 


“ANALOG 


past 1.6 pis A/D CONVERSION TIME. 


8 CONTINUOUS ANALOG OUTPUTS 
0-2.56V OR O-5V FULL SCALE. 

8 ANALOG INPUTS 0-5V. 

ADDRESS. PICKS CHANNEL. 

DIP SWITCHES SELECT MEMORY OR 
I/O MAPPING AS WELL AS WHICH 
BLOCK OF ADDRESSES ARE USED. 

CAN USE ZX POWER SUPPLY. 

UNIQUE DESIGN ALLOWS EASY 
INTERFACING TO ANY Z80 CPU TYPE 
MICROCOMPUTER AND OTHERS. 

MANY MOUNTING OPTIONS TO ZX81. 

FINEST BOARD. NEWEST CHIPS. 

KIT $180. ASSEMBLED & TESTED $230. 


INTERFACE BOARD 
Schannels AtoD+DtoA 


~~ 


~ & 


g E, | aa $ 
aia a ie 


iii 


SOFTWARE EXCHANGE. OUR FLYER WILL MARKET OR FREELY ANNOUNCE YOUR PROGRAM OR APPLICATION. 


BUFFERED BUS/ DEVELOPMENT BOARD 
KIT $65. Bare Board $40 vw/comecrtor & manvar. 


UHF Modulator 


RIDS VIDEO INTERFERENCE. 
REPLACES VHF MODULATOR. 


$15 


CONNECTORS FOR 50 WIRE RIBBON. FEMALE TO ZX $7. 


MALE TO PERIPHERALS $7. GOLD PLATED. 


C hpt 


ELIMINATES VIBRATION PROBLEMS. 
USE BOTH CONNECTORS TO AVOID 
ROW INVERSION PROBLEMS. 


TERMS: MINIMUM SHIPPING CHARGE. CAL RES ADD 6.5% TA 
PLEASE SEND STAMP FOR MORE INFO. TO ORDER SEND 
CHECK OR M.O. OR CALL FOR COD. PRICES SUBJECT TO CHANGE. 


omputer 
301 16th Ave 


San Francisco, CA 9411 


EDSON ELECTRONICS OFFERS 


Educational programs for grades 
1-4 that reinforce what they learn in 
school. We also offer a digital dis- 
play load monitor for monitoring 
data from the cassette to the 
computer. 


Write to 
Edson Electronics 
P.O. Box 151211 
Tampa, FI. 33684 

for free info. 


NEWSLETTER 


EVERY MONTH OUR 
SUBSCRIBERS RECEIVE 
programs — projects 
reviews — articles 
and more! 


SAMPLE ISSUE AND FREE 
PROGRAM 


2-WEST 


send $1.00 (shpg.) 
BOX 2411 VISTA, CA 92083 


ontinuum 


RR ———— 


(415) 752 6294 


*** for TIMEX/SINCLAIR computers *** 


LOST IN SPACE (uses SLOW) 

UNIVERSAL INVENTORY FILE 

UNIVERSAL MAILING LIST 

UNIVERSAL COIN COLLECTION 
UNIVERSAL STAMP COLLECTION ... 
UNIVERSAL COMIC BOOK COLLECT .10.95 
UNIVERSAL BASEBALL CARD COLL .10.95 
UNIVERSAL RECORD ALBUM COLL . .10.95 


Each program on cassette + manual. (8K 
ROM, 16K RAM) Please add $1.50 for ship- 
ping and handling. N.J. residents add 5% tax. 
M.C. HOFFMAN CO. P.O. BOX 117, 
OAKLAND, N.J. 07436 


LEARN TO 
PROGRAM 


Text and File Managers with 
ZX DATA FINDER 
A high capacity information storage and 
retrieval tool for 16 K Timex and Sinclair 

Computers. 
Advanced file input and editing routines 
are thoroughly analyzed. 
Comprehensive search and display 
methods are fully explained. 

AN ADVANCED COURSE 

IN DATA HANDLING 

Free specifications are available, or Send 
$9.95 for program listing and text to: 


THOMAS B. WOODS 
P.O. Box 64, Jefferson, N.H. 03583 


si 
sirike  catis-t? geb 
price a Mo nee 
Hav F A p 
qv ee ER 


GANS ia iss 


de 
tion INC!” me ges xen > 


How many times in glancing through 
a newspaper have you noticed a listing of 
current stock prices? Some of us might 
feel awed by the pages of strange sym- 
bols and numbers, while the profession- 
als are probably spending needless hours 
performing the tedious caluclations re- 


quired to analyze this information. To. 


aid these frustrated individuals, 
SOFTSYNC, Inc., has created a soft- 
ware package called The Stock Market 


Rudolph M. Daniel, 67 Manhattan Ave., Brooklyn, 
NY 11206. 


Calculator, appropriately named be- 
cause its primary function is to help the 
investor (or user) solve the complex 
equations inherent in Investment 
Analysis. 

The entire package consists of two 
programs. The first is divided into three 
sections: 

(1) Net Price Worksheet 

(2) Profit/Loss 

(3) Covered writes 

The. first section (Net Price 
Worksheet) derives the buy and sell 
prices along with their respective com- 


mission. This calculated commission 
should be used as an approximation of 


the actual commission because these 


charges tend to vary with each broker- 
age house. However, figures calculated 
by the program should be “extremely 
close? to the charges at most major 
houses. (A better idea’ would have been 
to make the rates variable in accordance 
to user needs.) 

The second section (Profit/Loss is as 
useful to the seasoned investor as it 
would be to the armchair speculator. 
Learning the “bottom line” of a finan- 


OMNI TEMPLATE 
FOR ZX-80 and ZX-81 


WHAT IS OMNI TEMPLATE? 

It isa template program for generating other programs. 

While developing programs, our staff needed a collec- 

tion of general utilities to avoid the burden of repeating 

the same routines over and over. This gave birth to 
| OMNI TEMPLATE. We found it so effective that we 

decided to share it with others. 


WHY SHOULD YOU HAVE IT? 

It is a great training tool. It helps you to develop a habit 
of writing professional-looking programs rather than 
rag-tag patch works. It makes programming fun. 


WHAT DO YOU GET? 
You will receive a cassette tape of OMNI TEMPLATE 
Program prerecorded and ready to use. Three addition- 
al programs: RACING, CALCULATORS and FIT- 
POINTS, which were developed by OMNI TEMPLATE, 
| are on the tape in addition to OMNI TEMPLATE. A 
complete listing of OMNI TEMPLATE and a well- 
documented manual describing how to use OMNI 
TEMPLATE is included. 


| HOW DO YOU GET OMNI TEMPLATE? 


It is $14.50. Please add $1.00 for shipping and handling. Send 
money order or check to: 


| Omni Technology 
| P.O. Box 10630 
Pittsburgh, Pa 15235 


| PA resident please add 57 cents for PA sales tax. 


* McKelvie Programs Specify: 16K RAM @$14.95____ 


GamelMaster. 


A NEW CONTROL SYSTEM FOR 
ROLE-PLAYING FANTASY 
ADVENTURE GAMES* 


~ If you enjoy role-playing games, 
but find the dice-rolling and 
record keeping a drag, let your 
ZX81 or TS1000 take over these chores. GameMaster 
for 16K RAM lets you create characters and monsters, 
use them during play, and then save them on tape. It also 
speeds combat and provides many other features. The 
1K version provides automated dice rolls, eliminating 
the need for expensive adventure game dice. 

*GameMaster is not a game itself, but an aid to role-play 


. P.O. Box 53076 1K RAM @$6.95___ 
- Phila., PA 19105 pa res. add 6% sales tax (Overseas add $1) 
e Check) MCL) VISAL) Card # 


Exp.Date_ Signature 
ame 


ddress 


> Z 


| 


SYNC Magazine 


cial transaction is crucial to all individ- 
uals. E.g. If you were to buy 100 shares 
of stock at a price of $23 per share and 
sell the same stock at a price of $27 per 
share, the result calculated by the pro- 
gram would appear as follows (See Fig- 
ure 1). 

Both of the previously mentioned sec- 
tions can be used as a learning tool for 
the novice investor or student interested 
in seeing commission charge fluctuations 
and profit/loss figures for varying size 
transactions of stocks or contracts, par- 
ticularly because of the speed of the 
program. 


Figure 1. 

BUY i998 SHARES AT 23 
SELL 100 SHARES AY 27 
COMMISSION: 

ON PURCH 61.85 
ON SALE 67.37 
NET DOLLARS: 

ON PURCH $2561.05 
ON SALE $2632.63 
PROFIT: : 
$271.55 (11.5 PCT? 
E PRESS ANY KEY 


SOFTWARE BY 
C.E.D.CORPORATION 


E-Z BOOKKEEPING FOR SMALL BUSINESS (TAKES LESS 
THAN %2 HOUR PER MONTH). ALSO GOOD FOR 
HOUSEHOLD BUDGETING. 

CHECKING ACCOUNT (MAKES CHILDS PLAY OF THIS 
JOB) 

BY-IT-SELF ITS GREAT BUT IT WAS DESIGNED TO WORK 
WITH E-Z BOOKKEEPING 


MACHINE LANGUAGE NIT-PICK (GREAT FOR LEARNING 
ASSEMBLY LANGUAGE PROGRAMING) 


WORD PROCESSOR (IT WAS USED TO WRITE THIS AD) 


ORDER FROM C.E.D. CORPORATION 
P.O. BOX 222, SALEM, WISCONSIN 53168 


PRICE LIST 
TAPE LIST BOTH 

E-Z BOOKKEEPING $19.95 $895 $27.95 
CHECKING ACCOUNT $9.95 $595 $14.95 
ABOVE TWOASA 
PACKAGE $41.95 
M.L. NIT-PICK $18.95 
WORD PROCESSOR $18.95 $7.95 $25.95 


SPECIFY ZX80-1 OR TRS 80 COLOR COMPUTER 
ZX80-1'S NEED 16K RAM 
TRS 80 NEEDS 16K RAM 


ALL OF OUR PROGRAMS ARE MENU DRIVEN AND ALL 
DATA CAN BE STORED ON TAPE AND OR SENT TO ALINE 
PRINTER 


WE HAVE TELEPHONE SUPPORT FOR PROBLEMS OR 
QUESTIONS 
CALL (414) 276-8787 


We guarantee replacement of defective tapes 


January/February 1983 


IF YOU DON’T MIND DOING IT YOURSELF, YOU 
CAN HAVE THE MOST FUNCTIONAL, AND EASIEST 
TO USE KEYBOARD AVAILABLE FOR YOUR ZX81 
OR TIMEX/SINCLAIR 1000. 
SIZE KEYS WITH 46 AUTOMATICALLY SHIFTED 
FUNCTIONS, CONVENIENT EDITING/GAME KEYROW, 


AND SPECIAL GRAPHICS SECTION. 


WE WILL SUPPLY THE DOUBLE SIDED PC BOARD, 
3 COLOR SILKSCREENED KEY LEGENDS, PARTS 
LIST, AND COMPLETE INSTRUCTIONS FOR $30 OR 


WE WILL SUPPLY THE ENTIRE KIT FOR $80. 


ALLOW 4 - 6 WEEKS FOR DELIVERY. 


$4 FOR SHIPPING AND HANDLING. 
RESIDENTS ADD 6 PERCENT SALES TAX. 


ADDITIONAL INFORMATION SEND SASE. 


Again the resulting profit or loss will 
vary slightly due to the approximated 
commission rate, but consequently the 
total calculating time by the program 
was under 2 seconds. 

The third section (covered writes) is a 
bit more complicated and- basically 
geared towards the investors familiar 
with different market hedging strategies 
and the concept of call options. E.g. see 
Figure 2 and 3. 

The right side of Figure 2 represents 
the information required to calculate the 
appropriate “cover” for a specified 
position. 

NOTE: You can only cover buys of 
“round lots” (multiples of 100). This is 
because 1 call contract fully covers 100 
shares of stock. The resulting output 
(Figure 3) does return to you a surplus 
of important information concerning the 
factors involved in covering your desired 
position. And at this point, previously 
defined variables (from Figure 2) can be 
altered and the results recalculated. To- 
tal calculating time for this section is un- 
der 5 seconds. 


KEYBOARDS 


FEATURES 73 FULL 


RESEARCH APPLICATIONS PRODUCTS 
4561 Paloma Lane 
Yorba Linda, CA. 92686 


INCLUDE 


CALIFORNIA 


FOR 


97 


The second program on this tape re- 
peats the Net Price Worksheet and adds 
a section called the “Write Unwrapper.” 
This section can be considered comple- 


Figure 2. 
2# COVERED WRITING WORKSHEET £ 


ENTER THE FOLLOWING DATA. 


CURRENT DATE -MONTH p te 
-DRY Se 
-YEAR Sa 
STOCK SYMBOL ISrt 
STOCK age s6 
NUMBER SHA 29098 
aaan DIVIDEND /SHARE & 
NBR MNTS PECTED 4 
OPTIO EXP MONTH FES 
OPTION STRIKE PRICE S& 
OPTION MARKET PRICE 2 
HARGIN INTEREST RATE i? 


mentary to the Covered Writes section 
in the previous program. In this section 
you input your past “covered” position 
and the program outputs your financial 
position if you were to sell your stocks 
and repurchase your previously written 
calls. Total caluclating time for this sec- 
tion is again under 5 seconds. 


Figure 3. 
### COVERED gai uggkaneer Fero 
73 
BUY 200 IBM AT S8 YEO -14 
“SELL 2 FEB SS CALLS AT 2 
DEBIT 54 DAYS TO EXP ay 
MGN RATE 17 
uR- 
+ CASH 


+ 
CAPITAL REQUIRED * 1102033 
EXERCISED RTN 18.11 ANN 75.95 
SAME PRICE RIN 16.15 ANN 67.76 
BREAKEVEN PRICE? / SHARE $47.12 
## MARGIN ## 
REQUIRES 


CA : 
EXERCISED RTN 33.13 
SAME PRICE RTN 29.97 


Besides the fairly well-written pro- 
grams contained in this package, users 
will find that the documentation is also 
excellent. You are given definitions of 
terms used and data by which to check 
computer calculations. This is one of the 
most important points to consider when 
purchasing software, and one of the rea- 
sons why the Stock Market Calculator 
has something for everyone. R.M.D. 


Fa 


CAR LOG 
A new USEFUL suite of professional 
programs for the ZX81(16K). 
1.) Very simple to use with full instruc- 
tions. 
2.) Complete cassette record of mileage 
and itemised expenses. 
3.) te conceivable ratios, totals and 
ojections computed. 
CAR fy G is suitable for your car, your 
dad's car or your whole fleet of trucks. 
Only $14.95 
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98 


Software Review 


The ZX Data-Finder 


James P. Cripps 


The ZX Data-Finder is one of quite a var- 
iety of data handling programs now available. 
Typical uses for such programs include: 
names & addresses; inventory catalogues; 
customer/client records; graphic charts; 
product descriptions; statistics; appointment 
calendar; personnel files; hobby collection/ 
with cross referencing. ZX Data-Finder does 
these and more because the flexibility of the 
program lends itself readily to a wide variety 
of applications. 

Files can be added as needed and are set up 
simply by assigning names. By assigning the 
same name to files itis possible to extend each 
file to the limits of user memory. For example, 
my “phone” file has eight screens full of 
numbers. In addition I have a file set up for 
each of the coming six months. Each file con- 
tains appointments, anniversaries, birthdays 
as well as reminders of upcoming events or 
obligations for that particular month. 

Individual file length is not preset but can 
expand or contract as items are added or de- 
leted. The maximum length of each file is 
fourteen lines (the total display area). The re- 
maining lines are devoted to providing the 
program options available to the user. 

Functions include: “ADD” for creating 
new file headings; “EDIT” for adding, alter- 
ing, or deleting lines of existing files. The 
ADD/EDIT mode incorporates a moveable 
blinking cursor to select the desired line for 
editing. 

The DATA-SEARCH/DISPLAY functions 
include: 

1) “Title search” to find all files with the 
same title and display them as they were origi- 
nally set up. This feature allows storage of text 
and graphics. 

2) “Word search” locates files which con- 
tain a requested word, symbol, or phrase. A 
simple procedure can be used when attempt- 
ing to recover data if you have forgotten the 
category you entered it under. 

After every display you have these options: 

1) Continue searching for the next item. 

2) Begin a WORDSEARCH and list all ap- 
propriate file headings (file indexing). 

3) Begin a word search and display com- 
plete files. 

4) Return to a previous file display of the 
same title (this feature allows easy back and 
forth referral between text of files which are 
longer than one screen in length). 


James P. Cripps, 4 Hackmatac St., Central Islip, 
NY Ft1722: 


5) Begin a new file search. 

The most noticeable shortcoming of other 
programs that I have seen is that the user is 
confined to one set format for a file once it is 
started. For example, if a file is set up as 
“Inventory” then the entire file would natu- 
rally lend itself to data formatted specifically 
for that purpose. Frequently the file space al- 
lowable is more than the user needs yet the 
remaining space cannot be used for other 
files. 


Then, if data retrieval from a file named 
“Addresses” is desired, the user must LOAD 
it from yet another cassette. A few repetitions 
of this kind would lead to the conclusion that 
the computer is not geared to serious data 
retrieval. 


In contrast, the ZX Data-Finder allows the 
user to design each file required to the exact 
specifications needed. 

One LOAD would then give information 
from any number of different files instantly 
without constantly reLOADing from different 
tape files. 

The amount of data the ZX Data-Finder can 
hold in just 16K is surprising. It has a carefully 
designed system which uses rather sophisti- 
cated string manipulation to squeeze the most 
out of the 16K pack. 

The program listing also comes with exten- 
sive documentation which is a comprehensive 
course in how the Sinclair ZX81 or T/S 1000 
handles data string manipulations. This pro- 
vides an understanding of file handling which 
I have not found anywhere else. 

In conclusion, this is the most useful and 
economical program dedicated to the task of 
data handling that I have found yet. 


SYNC Magazine 


Starblasters 


Dan Tandberg 


In “Starblasters” you must defend a sector 
of space from the invading alien spaceships. 
Your weapon is a powerful ion beam. But be- 
ware!!! The aliens can fire back. They can 
blow up your ship or even overrun your sector. 
Although you have five excellent ships in your 
fleet, you must be quick, skillful, and some- 
times lucky, to hold the aliens off. 

After LOADing and RUNning the pro- 
gram, you will be offered three levels of diffi- 
culty to choose from. In the harder versions 
you must press “1” more quickly to fire your 
ion beam (lines 340 to 360). The aliens will 
fire at you more frequently each time you fire 
at them and miss (lines 130 and 310). They 


Dan Tandberg, 4130 Coe Dr., N.E., Albuquerque, 
NM 87110. 


Line notes: 

80: YOU FIRE. 

150: ALIEN FIRES. 

190: MOVE. 

380: YOU HIT. 

390: Inverse space, inverse period (2), in- 
verse space; inverse period (4); inverse 
period, inverse space (4); inverse period, in- 
verse space (2), inverse period; inverse 
period, inverse space (2), inverse period; in- 
verse space (4); inverse space (4). 

470: ALIEN HIT. 

480: Inverse space, inverse period (2), in- 
verse space; inverse period (4); inverse 
period, inverse space (2), inverse period; in- 
verse space (4); inverse period, inverse space 
(2); inverse period; inverse period; inverse 
space (2); inverse period; inverse space (4); 
inverse space (4). 

590: OVERRUN. 

600: Inverse space, inverse period (2), in- 
verse space; inverse period (4); inverse 
period, inverse space (2), inverse period; in- 
verse space (4); inverse period, inverse space 
(2), inverse period; inverse period, inverse 
space (2), inverse period; inverse space (4); 
inverse space (4). 

700: SET POSITIONS. 

750: RESET YOUR POSITION. 

800: SETUP. 

830: Inverse space (4), STARBLASTERS, 
inverse space between each letter, inverse 
space (5). 


850: Inverse space (32). 930: Inverse — (32). 


880: LONG STRINGS. 940: G (32). 
890: 6 (32). 950: Inverse period (32). 
900: F (32). 960: 7 (32). 


910: Inverse + (32). 970: Inverse space (32). 
920: Inverse = (32). 980: SHORT STRINGS. 


990: Inverse <, inverse zero, inverse >. 

1000: Inverse <, inverse =, inverse >. 

1010: Inverse space (3). 1140: Inverse period. 
1020: INITIALIZE. 1170: ALIENS WIN. 
1090: STARS. 1270: EARTH WINS. 
1120: Inverse *. 1370: INSTRUCTIONS. 
1130: Inverse period. 1590: END. 


January/February 1983 


8K ROM 
16K RAM 


also fire at you more frequently each time you 
destroy one of their ships (lines 560 and 310). 
These effects are much more noticeable at the 
higher levels of difficulty. You guide your ship 
with the arrow keys: “6” for down and “7” 
for up. The pauses at the end of each wave of 


1@ REM 


“STARBLASTERS" 
7a 


; 2 
130 LET FIRE=FIRE+{.4-D-1e) 
i4@ RETURN, 


EN ' shu Sea's kT Le 
368 PRINT PF ER Tet TO CAIRAT 
RA. ee HS a CHR; ar RAA,@;Ust TA 


ZA); AT RAS SHS: ro CAI; AT RAQ; Ff 
$¢ TO ca iar RRA, *$i FO CR} 
178 IF R=RA THEN Gera zag 


; =C> 
250 LET CA CA- T 

Sa LET RRA=RB+ (RNO 1.5 AND RAILS 
RND>.S AND RAPE? 


~(INKREYS = 7"— AND Ro 2) 


TE Ys 
398 oF RND<(FIRE+DIFF) THEN Gos 


20 IF C»=tCR THEN coroa 520 
330 REM CELRAY FOR FIRE 

2408 FOR I=1 TA D 

350 NEXT I 

S6@ IF INKEYS="1" 
Ss7@ GOTO aa 


THEN GOSUB Se 


352 REN 
zoa PRINT AT “ATF 


“RE R+1,0; “E 
“JAF RELLO” 


460 LET R=RA- (RA? =18)3 #INT tRND + 
T2) +4(RA<180) INT (RND#D+2) 
#4190 LET C=@ 


420 LET SPARS ae er oe = 
438 PRINT AF 23,3; “SHIFS= “j 5HI 


4420 IF SHIFS<=@ FHEN GOTO 1:3272 
458 LET Ee 


"498 LEF RASR- (R>=28) INT 
3}+iR<1B) INT (RND #3? 

Saa LEF CA=28 

510 LEF ALTENS=ALIENS-2 

S209 PRINT AT R, CR$ 

S530 LEFT C=0 

ee nt AT 21,28; “ALIENS= "75 


550 IF ALIENS<=@ THEN GOTO 1270 
S60 LET DIFF =DIFF +4.37 (D#URVEsS} 


S7@ LET FIRE=0 
S580 GOTO i98@ 


pru, F AT R ain ER aT RC: 
AT RC,’ Ba 

SAT -iei "RT R+i.c;° Y 
“IAT R-1,0; “IRT R+i,0;° 


arte PRINT AT RAX,CAX;RS;AT RAC 


eons. Fa cA): AT RRA, 
RT RA, 0; J$: a cm: 
i jst F 


cA 
63@ LEFT RAX=RA 
64@ LET CAX=CĦ 
550 LEF tcrH=CA-1 
660 LET RA=RA+ IRA =9) -IRA>11I? 
670a IF tcR<=@ FHEN GOTO 11782 
68@ GoTo Gle 
aga oe END OF OVERRUN 
Zio LET RASS+2 SINT TRND F8) 
720 LEF CA=28 a 
730 PRINT ATF 21,28; “ALTENS= 7 


2; 
Af batak B HEE 
pat 


760 LET R=RRA-iRA?=Hi NT CRND& 
SI +(RA<2@) INT 


aliens or after losing the game can be ended by 
pressing any key (except the SHIFT key). 
Press BREAK when you wish to stop playing. 
The dramatic “ion beam” effect (lines 110, 
160, and 620) is produced with long strings of 
characters which are neatly sliced to the 
proper length and then rapidly printed one 
over the other using a single PRINT AT 
statement. Even if you do not try the entire 
game program, you will enjoy experimenting 
with this effective visual display technique. 


770 LEF C=i 
780 PRINT ATF 21,3; ” 


SHIPS = 


890 LET nS mman sone 


Feü. 
LET AL TENS SUAVE *S 

1070 GOSUB 78e 

1030 GOSUB 7Se 


in 
INF IRNO3ID?) IFF 
(RND X31? ; a 
1130 PRINT ‘ar A+INF tRND#293 INT 
TRND#322); 


1148 PRINT PT 1+INF (RND#i9) , INT 
(RND#32) ; i’ 


ASE 
4198 LEF FOTRL =TOTAL +VAVESS-AL IE 


1200 CLS 
1210 PRINT AT 4,43; “You FAILED- -- 


a 
1220 PRINT AY 2,3; “THE ALTENS GO 


3238 PRINT AT 22,3; '¥YRUi PESTROYES 
TG taboo GHIPS., 
1240 PRINT AF -ERA iPUSH TO TRY 
AGAIN. 


2258 PAUSE icang 
2266 REM ME za 


1290 LET TOTRL =TOTPAL #UAVE SS 


1310 LEF NANE LBE +i 
3328 PRINT AF 2,3; “HGHSRATULAT TS 


133@ PRINT AT 22,3; "A SUCCESSFUL 
DEFENSE.’ 
1340 PRINT AT 21.3) “(BUT WAVE 


Rom, 
‘ow PTY 


"DIFF SCULLY? 


S18 PRINT 

1528 PRINT "2 IS HARO” 

1530 PRINT “2 IS MECIUM” 

TSAA PRINT "23 IS ERSY" 

i556 PAUSE 10000 

4566 L O=UAL INKEYS ot 
i578 IF DoS OR D:1 THEN GOTO 255 
15eg RETURN 

1599 SD 


Vu-Calc 


Ken Uston 


In “spread sheet” programs, one of the 
most well-known of which is Visi-Calc, 
we expect to be able to handle budgeting, 
whether personal or for small businesses, 
to work out complex mathematical prob- 
lems, and to have the flexibility to 
accomplish other tasks such as calculating 
compound interest tables and recording 
the answers. Vu-Calc successfully meets 
these requirements. 

Vu-Calc, developed for the Timex/ 
Sinclair 1000 with 16K RAM, displays a 
table of 36 columns (numbered 01 through 
36) and 26 rows (designated A through 
Z). Each of the 936 boxes can store up to 
eight characters, alpha or numeric. The 
screen displays 27 boxes at a time, three 
columns by nine rows. The “window” to 
the table scrolls rapidly, however, in any 
of four directions, allowing easy visual 
access to the entire table. 

The user may input up to 40 formulas 
with up to 32 characters. Any of the boxes 
in the table can be used to store the 
answers. We can include in the formula: 

1) The four basic arithmetic operations 
and exponents. 


Ken Uston, Jockey Club #422, Las Vegas, NV 89109. 
DN 


BG 


presents the 


eae 


. Play and create high resolution games 
. Create your own character sets 

. Includes 2K of memory 

. Use easy to read reverse video 


- Demo tape with character sets 
- Zap-Em high resolution game 
- Spyder Software Catalog 


Bare Board -$14.50 
Kit -$24.50 
Assembled -$29.50 


Send check or money order to: 


USA funds only 


100 


To 
Cay 


ELECTRONICS 


SPYDER CHARACTER BOARD 


. Compatible with RAM Packs and ZX Printer 
. Installs easily (Complete instructions included) 


Included with the Spyder Character Board: 
- Fult documentation to get the most from your ZX81 


Add $2.50 for 
postage and handling 


SPYDER ELECTRONICS 


2) References to any of the boxes in 
the table, from the very first (upper left) 
box “A01,” to the last (lower right) box, 
“Z26.” 

3) Constants such as A, B, X, Y, or Z, 
which can be assigned different values 
(these are particularly helpful in 
answering “what if”-type questions). 

For any of the formulas, it is possible to 
generate a series of answers for each of 
the boxes in a given row or column. The 
answers can either be “absolute,” 1.e., the 
formula will be repeated with the same 
box numbers therein, or “relative,” 1.e., 
the box numbers are incremented by 1 as 
the program progresses to each consecu- 
tive box. Thus, if the formula for A02 is 
“A01+10”, under the “relative” option 
each box through A36 will contain a value 
that is 10 greater than the previous box. 

When the program is LOADed, the 
main menu appears and gives the user the 
options: to begin with an empty table, to 
continue working with the existing table 
with the information contained thereon, 
to save the program on the cassette with 
the existing table data, or to save the 
program with no table data. 

The program has a number of helpful 
options, such as repeating formulas al- 
ready typed in for other boxes, moving 
the cursor immediately to the first box 
(A01), and, for those users who have a 


printer, to print the contents of the 
screen. 


Uses for VU-CALC 

Vu-Calc is helpful in applications where 
the user must prepare spread sheets or 
matrixes which require mathematical 
operations. Here are some examples: 

1) Let’s say that you want to calculate 
the cost of 15 different items for each of 
the next 33 years (through the year 2015), 
assuming an annual inflation rate of 9 
percent. We will list the general steps 
necessary to do this so you can get a 


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clearer picture of how Vu-Calc works: 

a) Enter the names of the 15 products 
in the first column, in boxes C1 through 
Q1. 

b) Enter the year in the second row of 
the program, putting 1982 in B02, 1983 in 
B03, and so on, until 2015 in B35. 

c) Enter the current cost of each of the 
items in the second column, in boxes C02 
through Q02. 

d) For Box C03, enter the formula 
“C02*1.09”. Use the “relative” option to 
extend this through C35, effectively com- 
pounding the cost for each of the next 33 
years at a 9 percent increase. 

e) Repeat Step 4 for the 14 other 
products. 


f) Hit “C” and the data will be calcu- 
lated and posted to the appropriate boxes 
in the table. See the sample printouts 
below. 

2) Another use for Vu-Calc is keeping 
track of income and expenses, whether 
for personal or business use. For example, 
a dozen or more line items could be kept 
on each row, identified in the first column 
by a letter. The other columns could 
represent months, weeks, or days. 

Although the limitation of 32 characters 
per formula makes it impossible to add 12 
months to get annual totals, sub-totals 
such as quarterly data can be used. These 
can be added to derive yearly totals. 

The formulas can be set up to add 
horizontally for line item totals and ver- 
tically for the period totals. 


January/February 1983 


3) Using a similar format, Vu-Calc 
could be used for individual budget con- 
trol. Budgeted amounts for various types 
of expenditures could be posted to every 
third column. Then actual information 
would be entered, as it become available. 
Formulas could be entered to calculate, 
for every third column, the amount, for 
each item, by which the budget was ex- 
ceeded or (if you are thrift) undercut. 

4) We could calculate the value of 
various investments at varying rates of 
appreciation or depreciation. 

In summary, Vu-Calc is potentially a 
valuable tool for many owners of the 
Timex/Sinclair 1000. The uses mentioned 


here merely scratch the surface. Other 
jobs to which Vu-Calc may be assigned 
are limited only by the creativity and 
imagination of the user. 


e ELIMINATES SLIDING 
ACCURATE TYPING 
& LOSS OF PROGRAM 


CASSETTE HOLDER 
e 2 YEAR WARRANTY 


TWO GREAT 
ADVENTURES IN 16-K 


DRY GULCH — Search for Treasure in an Old West Ghost 
Town. 


MORLOCK CASTLE — Will you survive the hunt for the 
Magic Medallion. 


$9.94 Each (on cassette) 


Each Interactive Adventure is written in the classic style and 
has over 100 words of vocabulary. 


UPSTATE LABS 
27 Elvira Street 
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FIVE VIDEO GAMES 
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Video listing for the ZX81 or TS1000 
with 1K (1 prog. requires 2K). All games 
feature moving graphics. Package in- 
cludes S-Invaders, Grandprix Il, Astroid 
attack (not like astroids), Nuke 2K and 
Sinclair destroyer (softSync Sells 
identical copy of this public domain 
program for $7.42 on cassette). 


Four 1K one 2K listing for only $2.95 + 
70¢ postage and handling NY residence 
21¢ sales tax 


Frog Software Company, P.O. Box 95 
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gram FREE 


e ELEVATES AND TILTS KEYBOARD FOR LESS FATIGUING, MORE 
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$7.49 ea + $1. handling and Postage. SEND CHECK & ORDER TO: 
ZOPF INDUSTRIES 121 W. Mt. Hope, Lansing, MI. 48910 


101 


8K Updates 


In the first issues of SYNC the programs 
were all for the 4K ROM. When the 8K 
ROM became available, we 
wherever possible to provide listings for 
both ROMs. Since we have had requests 
from readers for updated versions of some 
of the programs we published earlier, we 


tried 


will include these from time to time. 
Forest Treasure 
ia alate 38 ESE 3x1 72 22 
In Forest Treasure a treasure (shown oe ee ye 
as a blank space) is hidden in the forest. ae eer F 
You (shown as a pound sign) are search- $o PRINT AT 20,6: “FOREST TRERS 
ing for t. Enchanted walls which’ aré - "Ss Ler PAIRT cenp sce) 
invisibie- may throw you off into a differ- 298 rer Oon (RNG Sees. 
ent direction. Monsters (shown as M) may Soet ia PEEK 16S596+2562PEERK 156 
pounce on you, steal the treasure, or kill E Rt ae TO TE rei Sea 
you. Then you lose. However, they can Pee ee er EEEE 
170 IF A ssSSiINt” fess THEN GOF 


even duplicate themselves. If you get the 
treasure, you win. You control your 
movements by U, D, R, L and then press 
ENTER. Entering S will exit you from the 
program. 


Paul 


60443. 


102 


G 168 


297+M. 50 
1908 


6 380 
6327 +H 
230 IF PEEK N 
POKE N.12 
250 IF 


INPUT A$ 
PRINT AT 


ABERSOF I 


7 MAESAFALLEN, BOW ST, DYFED, SY24 5BA 


ZX81 & Spectrum 
Games 
Now NEW LOW prices!!!! 


PROGRAM 


Chess 1.4 
10 levels mc 


Frahm, 21123 Dettmering, Matteson, IL 


PRICE 
$17.95 


Adventure $17.95 


140 locations based on the original 


Invaders 
Fast mc arcade action 


Mazeman 
All the features of the original 
arcade version m/c 


Add $2.00 for postage/handling 


2206 LET N=PEEH 


18@ POKE PEEK i8S396+256+PEEK 16 
IF M=T THEN GOTO 4939 
210 IF H/33=INT 


23 
{He SS} TREN GOT 
16395 +2536 PEEK 1 
=505 THEM GOTO 469 


H=T THEN GOTO 439 
26.25". 


Now you can 


e3 tone generators - 


and envelope generator 
e Noise generator 


audio output jack 


and most other modules 


programm 
e User selectable to the start of 
memory location 


input/output, or with joystic 


2 AMP 


This supply has it! 


z 


SOUND EFFECTS 


MUSIC GENERATION 


TWO 8 BIT 1/0- PORTS — 
DUAL ATARI JOYSTICK CONTROL 


The ARCADE MASTER 251 ano 181000 
KIT $54.95 e A&T $64.95 e PC Board $24.95 


8 octive range 
e3 channel mixer, amplitude controller, 


ALL INDEPENDENTLY 
PROGRAMMABLE! 


eInternal speaker, volume control, and 


e Requires no additional power supply 
e Complete instruction manual & examples 


¢Can be used with printer, 16K rampak, 
¢Memory m apie so it can easily be 
in basic using peek & poke 


02 Independent, TTL compatible I/O 
ports can be used as general papas 


POWER SUPPLY 


ZX80/81 © TIMEX 1000 ¢ MICROACE 
As you expand your system, you'll need 
more power to run it. 


2850 IF Ag="5S"* THEN STOP 

236 POKE N.22 

z0 FOR I=ł1 TO 75 

310 IF St(E}=H THEN GOTO 386 

320 NEXT IT 

aga : ARZUR“ AND <32 THEN LET 
F=F + 

val palo QAg=“L“ AND F:i THEN LET 
F=F- 

350 IF A¢="P“ AND E :20 THEN LET 
E=E+i 

Wee R¢é=“U" AND E>i THEN LET 
EzE- 

370 GOTO 1608 

SSO LET F=F4+4iINT {RND 9} -53 


3230 LET E=E+t INT t(RNO«*9} -5) 

#00 POKE PEEK i6396+2568PEEK 16 
SO?TtB(I3 .24 

416 PRINT AT 2@ i: “Se 


423 GOTO 160 
4303 POKE PEER 1683536 +256 PEEK i6 
SOF4eT . 142 

44@ PRINT AT 2@.i;'* 


450 GOTO 19 

466 POKE PEEK 16596+2562PEEK iG 
SS7tH. 175 

470 PRINT AT 26. Hy 


480 GOTO 5108 
490 PRINT ff 26.15" 


INT AF 21,1; “ `a 
51g “RNOTHER z 
528 Bt 
S38 
540 IF CODE B¢=62 THEN RUN 


558 STOP 


Graphics notes: 

30: A 

410: inverse: OOPS, YOU RAN INTO 
A WALL 

440: inverse: YOU HAVE TAKEN 
THE TREASURE 

470: inverse: THE MONSTER HAS 
KILLED YOU 

490: inverse: THE MONSTER HAS 
STOLEN THE 

500: inverse: TREASURE 


create complex arcade quality sound effects, 


write melodies in 3 part harmony, and control the action 
with one or two Atari Joysticks (not included) 


any 4K 


Ee Oe ws ot Se 
SAS SRE & wee & 


MULTIPLE OUTLET STRIP 
with built in 
TRANSIENT ABSORBER 
PROTECTS YOUR COMPUTER SYSTEM 
FROM DANGEROUS VOLTAGE SPIKES 
Absorbs transients and surges such as 
those produced by lightning, switchin 
surges and noise spikes. 3 protected A. 
outlets, 15 A. fuse, pra switch & pilot 


ord 
SPS-2A -- Power Supply -- $19.95 TA3 -- TRANSIENT AB: ABSORBER -- $26.95 


Send check or money order to: 


HURRICANE ELECTRONICS e P.O. Box 87 e Dolton, IL 60419 
Include $2.50 shipping/handling per order -- Ill. residents add 6% tax 


SYNC Magazine 


yy 


Defuse 
Raymond Fowkes 


You are in a one million room building 
which has a bomb hidden somewhere 
inside. Fortunately, you have a bomb 
detector that registers a signal that get 
stronger as you get closer. 

Enter the listing and press RUN and 
ENTER. The type in the coordinates of 
the room you want to test (length, width, 
height from 0 to 99) and proceed accord- 
ing to the signal you receive. You have 
200 seconds before the building blows up. 

To edit in 1K you must LIST the line, 
press CLEAR and ENTER and then 
EDIT. Do your editing and hit ENTER. 


(RNO JIia? 
(RNO 4100? 
(RHD IAR 
@ PRINT AT 19.8; “L tf H 


aree Fa 200 STEP 18 


4 
INPUT F 
PRINT THE 8;F, 
(R-P? +ABS (8-£234+A85 


SCROLL 
SCROLL 


Š; TRB 23; 1E4+- 
fC-Fli+* 


SND B= ANE C=F THEN 
ic <i HH IT WAS AT 


Me. Er Use" 


mme : 


Raymond Fowkes, PO Box 336, Coalinga, CA 
93210. 


magazine binders 


-= hold a year’s issues on 

% individual snap-in rods, 
combining them into one 
volume. $7.95 each; 3 
for $22.50; 6 for $42.95. 
Mixed titles OK for 
quantity prices. 


Open-back cases 

store your issues for individual 
reference. $6.95 each; 3 for $19.75; 
6 for $37.50. a 

Mixed titles OK 
for quantity 
prices. 


vey CHARGE ORDERS ONLY— 
for your convenience PHONE 24 HRs. 


TOLL FREE 800-345-8112 
In Pennsylvania only 800-662-2444 


January/February 1983 


Shelf Conscious? 


Now you can organize your copies of your Favorite Magazines 


Mastermind 


Raymond Fowkes 


In Mastermind the computer selects 
from six colors a code of four letters. You 
must discovered this code in no more 
than 9 guesses. Input your guess as a 
series of four letters (representing the 
colors ROYGBW). The computer will 
match your letters one by one with the 
selected code. A black peg shows that 
your guess was right in color and position; 
a white peg, that your guess was right in 
color, but wrong in position. Continue 
until you guess the code or run out of 
guesses. 


Continued on pg. 104 


Now your magazines can be a handsome addition to your decor, well 
organized, and easy to find, thanks to these durable library-quality 
cases or binders. They're made of luxury-look leatherette over high- 
quality binders board. And both styles are custom-designed for most 
magazines you save, with sizes, colors, and imprints selected by the 
publishers. FREE transfer foil included for marking dates and volumes. 


Jesse Jones Box Corp., Dept. ZD, 
P.O. Box 5120, Philadelphia, PA 19141 


Please send: [O Cases [O Binders 
QUANT. 
Title: 
Title: 
O ENCLOSED IS $ .* Add $1.00 


| 

| 

| 

| 

| 

| 

per order for postage & handling. Outside USA | 
add $2.50 per unit ordered. Send U.S. funds only. | 
| 

| 

| 

| 

| 

| 

| 

| 


| 
| 
| 
| 
| 
| 
| 
7 O CHARGE (Min. $10): O VISA 
| 
| 
| 
| 
| 
| 
| 


O American Express O Master Card 


Card # 
Exp. Date 


Signature 
Print Name 
Address 
City/State/Zip 


*PA residents add 6% sales tax. 


Mr. Berch has it! 


ZX81 Assembler 
2 pass, Standard Mnemonics 
Symbolic Expressions 
Decimal/Hex 
Now 100% mach. code 


2X81 Disassembler 
Std. mnemonics, Dec/Hex output 
Assembler plus disassembler 
$15 ppd (cassette) 


Serial Printer interface 


(thru mic port) plans & listing 


RS-232 ASCII output $5.00 ppd 
NY res. 
add 7% 


Bob Berch 
19 Jaques St. 
Rochester, NY 14620 


ZX81 VIDEO INVERTER ADDS PROFES- 
SIONAL TOUCH. 

NO MORE EYE-STRAIN. 

DISPLAY SHARP WHITE CHARACTERS 
ON SOLID BLACK BACKGROUND TV 
SCREEN. 

A TOGGLE SWITCH LETS YOU CHOOSE 
BETWEEN NORMAL AND REVERSE. 

THE SMALL PRINTED CIRCUIT BOARD 
FITS INSIDE YOUR 2X81. 

ALL FULLY TESTED WITH CONCISE 
INSTRUCTIONS. 

MONEY BACK GUARANTEE. 

AVAILABLE AS KIT £5 / $10 

READY BUILT £6.50/$ 13 

PRICES INCLUDE AIRMAIL. SEND £ OR $ 
CHECK. 

D. FRITSCH 

6 STANTON ROAD 

THELWALL 

WARRINGTON 

CHESHIRE 

WA4 2HS 

UK 


Everyone and his brother are copying video 
game ideas so we will too. 
| ING 
+RODUS es 
PITFALL FRED 


similar to Famous Atari video game cited in 
Omni Magazine December issue as one of the 
10 best video games of 1982 run through the 
jungle avoiding pits, snakes, and quick sand, 
while hunting for gold and money (16K ver- 
sion also has tarpits, fuzzballs, silver and 
gems) 1K, 2K, 16K version available (please 


specify) 

Pitfall Fred $3.95 for cassette. Plus $1.00 for 
shipping. 

Ny residence add 28¢ sales tax 


FROG SOFTWARE COMPANY, P.O. box 
95, Glenmont, NY 12077 or call between 4-5 
pm (518) 465-6552 


Help 
\N 


*mention Sync Magazine and get an amusing 
but otherwise worthless program FREE 


103 


Hangman 
Raymond Fowkes 


After entering and RUNning the classic 
game of Hangman, the first player inputs 
a word of up to 18 characters (32 for 2K). 
The screen is then cleared. The second 
player begins trying to discover the secret 
word by entering letters likely to be in the 


As tA) word. All correct letters are printed where 
4@ FOR B=SGN A a T ae ieee oe they occur in the word and any others are 
ewe et at printed in the center of the screen and a 
28 PRENT “ROYGBU MEN. boy part is added to the figure on the 
as a E as as 
aA LET R-NOT A ga OwS. Ee Sette ao te WORD 
e e A AY’. 9:Bs Typing in the lines below will cause the S8 CLS. g 
120 LET CS=AS program to accept characters without 50 PRINT “ is 
Ba lh die due OEE) THEN GOTO 1 pressing ENTER after each. Spaces, how- Z0 FOR A=2 TO 7. 
15@ PRINT AT 0.8; "m ever, will not be recognized: 30 NEXT A : 
nee a TR 
170 LET 83 (6) eng 190 PAUSE 4E4 110 PRINT 
130 LET C$ (E? =" E" ; 74 
190- NEXT E 195 LET C$=INKEY$ Ten bE eee 
200 IF B=A+A THEN GOTO 318 _ 40 140 DIM Ce {NOT F) 
210 FOR E=SGN A To AR Delete line 1 150 FOR BSE TO LEN A$-NOT F 
cae IF CE} «28st: THEN GOTO 2 170 NEXT B 
18@ FOR G=F TO 22 
24@ PRINT AT _O,8, "oR" 190 INPUT C$ 
250 LET B=B+2 ek ; = 
268 LET B$iF} ="dE" Graphics line notes: ES UN a RE eng 
270 GOTO ese 40: D (6 220 IF C$: AfA! THEN GOTO 266 
PR RA, 328 PRINT R, tage Cs 
300 NEXT D 50: 5 
310 PRINT AT NOT A,NOT A; "URONG Mee E eee 
"AND D=SGN D;TAB 4P," "IR$, 60: 5, A 270 IF F=6 THEN STOP 
328 IF P+ 2SGN D Lets PRINT INT 80: A 280 NEXT 
ene a Vey 00: A (11 220 SBIT HE atobe BR aT va 
. . $ = ie 
70: inverse space (8). 180: inverse space. z AQ. in es AE SISS8298° (Een és +NOT „B SUAL “S524 
150: inverse space. 240: A. BaT pose 310 NEXT 
300: A 320 PRINT AT G.NOT A;jB$ 


170: A. 260: A. 


$$$ ——— 


Index to Advertisers 


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PALA gh | Se REEE E PE EGA SE E E T A E R. 102 Frog SOP G6 sis esea aaen ar eee a eiA EATS 38, 92, 101, 103 PUTO! UBD EEE A E A E A TE anaes 94 
CN 1 1 PAEA R E R R E R O 67 Fuler Micra a atea avstapanceacacaecatongecnsce raps Nak E Eana 75 Picasa ntria eiicsirepre dorra csnracatabornspars eeso AREIS 92 
t a e A E T AE N A ANE N AIS 58 Peter Furlong: Products <ic..03. 20. icici. seis eeccceceasedeneoscedancnstsess 62 Powerplay SYStemms:.....206.5...0..cssscassvesencncoednsoedgagepentnessoosoveass 15 
Advanced: Interface Designs ioi.: niss ..ssecccceveceveeassnsscusssscagsive 67 Cae A RN on cas DAT PE otc N A hte 96 Powe trOn Goa. «552s raaa a cook tuasoee banter etna aAa 70 
WET t PEE EE RET Aaa oan abies e EN appa Tosca T E 50 Gladstone Electronics.......ccccccccccceseessececceeesscecccceceneeacers 52, 53 Professional Electronics ©, .s.csc.<cigasdiacqsSosandeteceseatitecnavsvanagecad 38 
A DEIO SOURCIN SOWAT sia dics sienna y cde senssesnecndsonetase dabas 54 Grae WS ions E A ods CEN bef ote 93 R Irr Associates: ioira cee icccs nae eiras apap ee es enon 51 
PAYOR. FOCHDOIORY. -tostis 0de ab idafovincp tossonetsooysewanepuctes 19 Haymarket Software ....cccsccssssssesssessssssecsssessecseecneennecneentenses 70 Harold M. Rabbie ad judi E E E E IT AS N: 93 
Atto-Soft sosesennesenseceueccnnecouscennecensecenscconecenncceunscessccancenasensnsge 31 Heath Computer Services .....sscsssesssesssessesssessseessecseeseeaneenees 72 RCO: Terminal ookee Aetate iope riene E Neri OSA Nai 11 
a E EET T EIE EE A E AAE A E TS 15 Hensley & Associates i.....sss.ccssscssssssscosssscssosestiberteclaeecaeeonsaé 92 Research Applications: .:..iccsciisisss.ccsipeccsesestevnnebvgeedthcenanesten 97 
EE a E O SR VM See Oy EPSON AO a EE APR el 31 MO PEO a tks ok Son oe A AT S 95 Reston Publishinp. ss. i.te eo davcccacesesdarcaceoatiaghoboscetommcbtianenal 57 
ORME NMR Cea yet cia E E hua tuna saat E N T 91, 103 Hanter OSes a a ee 17 Rom: Pac Applications ® oi0.. 5.0510. cissese cobecskeses tub eseboesie Cover 2 
EMR Behe Nad PAE T eek bad EE be aivods Geecadaviesins pacers gitgitee’ 21 Hurricane Electróhics u LS ee ee 102 MRP eas cp cain gis a a scouted cba hg ea as meas 66 
SORMAPIGTISICS COMPDAM adc cs ncexecnlatidhcasinsnesccdosaeucceanedscae 94, 54 : Rün-It SoftWare < .ciics.sscuiscshesiaswscotvosywectsaguaph eTA E VESSE 40 
en Conti. a cl ein 90 Infinity Research ..............ccccccccorecsesccocscsesbenssesesevenensevesvonsess 84 Sanik Ee Mauna 93 
o JERR E NE E ET tee Aj fitercom itor ie ae e e ole thant ene 39 itch O E e aT a S: 
OPE E E TEE E A I E A NAT Inira nam Publislitie anae cn: A P1 EE AAA R E E A a o S O Margene 
MN NO E T T a PE A SE TAS EEE I E T 5 ; SOL A iNe a ar A A qs bueenatane 71 
a e a E a B E A SOS A A E E E 18 NS dT is n r mAy E RA A RS! a 3 ServitPonics 665.5668... 8 ahd aA E e ASe SAAIE PAAA n peveafosion 60 
eR TEIN ait cine aa O tea hagas ei sabddo avedeosindovoovenens 55 IRS S p A AGE E D S A aney) AOE AAA YS BEET 87 Sight & Sound Electronics:..........0.......scseetessenssseocesesveesasensy 31 
AE TARR INE sk EE T AEA I EAT E EATE AEE 42 Se ree EE APET E S DAEA Sights & Sounds Systems .........ss.ssssrsssrssrsssrsssseisrnssnessensseese 94 
DA A PERE y EE BE EE RE PAEA A E EE 97 Kaltex ..-r..:.+s. ao liek E E hae a AR I NEA N 70 Simplex Software .....:.062000.1.liciscssssocssdeansemensedocdpamesepereasens 74 
Circle Chess ne issn 31 Dat te aT inher serene big ae Gee. oF Singlair Place ioniadh ea 65 
eva COmMmpüter Ware Sersan deese aico ESEE seeti a eeste 82 A n n a a cn ee eg E eee tres aes pte F SMW T a E PA S EE E E E E A R EE Oe 4 
Coure TEBE ats ee r dace as bo A S ave 29 oe poor Pre reer eae Piatt es ME ad ee R 94 SirittISWATC) ike... h2c3 cdl ces ea eo eee eds Gacy soca E AATE 3 
rath ere? P EEE ARE EE DHA E NENE S EEE RT 91 Aae FEALIONS ÎNC ......-..esssseersseerseseorsnereresscnsnsscennccnsneseen = SHOT WALES assis eee ninne t Gane pssina saceguissstccahoupenstetmmaamantnrie toes saint 61 
T SN 2 io sas E A oc soca eaceadasenabab abs E E OF i a ee eR ee a eee eh eet OG mene oe aT, MCT cScticesssanichachdonadesacsccensbsinechsetbeetegeanentnbansgasbatvaiene 
Computer ASSISI NCC. aa cicces cep capex Rhos! aet aeiio 87 Lambs Software ...........ssssssessssessssessnsssessecssssnsesssnesnsnsesnessen 94 aa Jas AARRE E AE E x 
Computer: Conun aiina iro e AR 95 Leading Edge .......ssssseseesrrsrrrrrserseresrerrerresrssetessennstrtnt Cover 4 The Software P a e a eee 
Computer Engineering Services ...........:cccccsessssecsseessesseneens 93 LJH Enterprises ..........sesssersssrrssrerssrrrrerrnerennsnrnnnnnennrnnnntttt 85 Southern Computer Systems ............scccssseseseecesessesesesesseseees 69 
er Lo) Bo RRS dai E NARA TR cp mee We 89 Luxtron NC oases essessesseeseessesneesessssenscnsenesnncnnssnecnscnncanenncesennen 60 Spyder Electronics- na Aren ernie a N AN iie 100 
CompuSoft LA EY AEE RV S pitied E A e ST 10 William Maples eererereerrerereeereeeseeeseeteeererereeeeeeereeeeseeereeeeneeeeees 59 Strátegem CybernetiCs esc: ss ckegst.tieessancathjapsacnnrdagestbavaneeste 28 
a eE T RE A AET A E A NA 83 M.C. ASSOCIAtES.....-..-eesesesereeeseeneneeneneenenterssessneananeonensnesneey 44 Oe ae Sis eae deo fe iE 46 
Dasdalus UWE a in atas an e 89 Melbourne House.........s.s.ccssesessesenenenenenenerensesenssenenenanenenens 63 Synergistic Deem en ast e SeN E Cover 3 
Data Assette VEIE A EEEE ET ye ae E EAE 8,9 Memotech seseeeeeteneeeeesesscesenansesenereeenseseanenneeaseeaasernensaaasananennees 7 Time- DOA Gk eee hits a eo 88 
DK OSB lp see Reps aes Beda eh cabanas gers 13 Micro-80 ........sssssessesseessssseesecssssnsoneenecsscsnsensesscssssesenseansnssetss 73 Troiano Software ano a N A 94 
D-Ram yng Re UD GE E AS are E A I AAE E Rema) L EE 93 Micro Computers PIUS ........02sceecsrceressccecsocoscsssescenssestessosense 37 Turner ERY I Ee Roler gsc anasnes i sibar ie ESERE 90 
Aae oe AET LA A E EA E AR A 25 Potties Sate CONCEPIS........seesereessesessesesresssseneseeenenenenenenenes 54 Upstate A ON os cesta cakes iy stesso ress d aodann taas skares Naairs 101 
U ERDAPET aces ioc E cach chs ona ROBE T rea as Tae cae cen pte 93 ICTOSYNC «...sseseseseseersrerenerenenenseesesesnsrsnsnensnensssasstsnsnenanansnaneees l L T EER AA EEN aE E T EOE E A 
Egoa peas ena cag eed ees ate aE coed Re e 95 Mes tect MIMS ........sccscecesesseseesersssessseseeseessseecsenseeseseasenenenees 59 Thee Wik [nb OF ESS ae ee Re: Rie MCLE I S eT a 
WGA Wied ASEA EN AI EEL F E EE EE 62 AE KO, RER PPE I EE AA TA E E a T T 98 York FO a e eh ec Ee 
Expense Cutlet nin: ne e pies dade ar e n EEE 45 Non-Trivial Solutions...............sscssssssssssssessersecerseseensseeenserens 6 Zopt industie nA ty Se OPEL Et PER CR te re 
EE gS) AUER ERE TE E CSM UPD po paint A ete fe eR E A 61 Omni Technology 6.5 csrke shoes trveress xs op ene <cavsdenstbadgshsteeseliaaeesd 96 Zor KHAM NOUS TICS «oes ccs exgavdsenvnssancespastpuepsnionesunpaatapteseds 31 
Ezra Group I e ET E E E N A EER A 41 Orbyté SoftWare nriran aeaaee sicotan stares a Ar ARE 2 Z X Pánding Lid: 5 os) cs cis instep 100 
Florida Creations E P stars vik uses gate RE cusp ica besa oaks ve EA 31 Ome EEE EEN A ae ip aesae krann MMPS RES ot URE 92 Be WUE Beene ho cis va S AEAN A esas ard a E AIS eee 84 
The Fourth COMTI PGI Ss cos danas AAAs eade a gadcdhs sti cussseatancdee 88 Panda POEL WR s antes Nees conv reassert sas irea aeS 47 TEA AS I NE AE E EEEN SAE A E S E T 95 


104 SYNC Magazine 


SINCLAIR/TIMEX USERS 


` NOW SYNERGISTIC OFFERS YOU THE ‘SMART™ CHOICE 
DESIGN 


THE SYSTEM LOGIC KBD-I 
‘SMART™ KEYBOARD 
ENHANCEMENT FOR 
SINCLAIR/TIMEX 
COMPUTERS 


SYSTEM LOGIC — KBD-1 


FEATURES SPECIFICATIONS 


e ‘SMART™’ shift function 

e Tactile feedback s , 

e 59 keys (with left and right shifts) Contact resistance: 202 @ 1mA 

e Standard (QWERTY) typewriter format Contact rating: 1.0V/A 

e Silk screen labels compatible with 
Sinclair/Timex keyboard Contact bounce: <5.0mSec. 

e Compact design en. 6 . 

e Rugged yet attractive black anodized Switch life: 5.0x10° operations 
aluminum cabinet typical 

e Simple installation 

e Custom engineered for Sinclair/Timex Switch force: <9.0 oz. 
computers Switch travel: .015 in. 

e Auto-repeat function (fast/slow modes) 


MAIL ORDER TO: 


SYNERGISTIC DESIGN 
P.O. BOX 411023 
CHICAGO, ILLINOIS 60641 *Illinois residents include 


6% sales tax. 


PRICE QTY. AMT. 
SYSTEM LOGIC KBD-!I KEYBOARD $85.95 * 
Shipping and handling (per unit) $ 4.95 fee $ 4.95 


Money order or check TOTAL 
NAME 

ADDRESS 

CITY 


THE PROWRITER COMETH. 


(And It Cometh On Like Gangbus 


EVOIUTION. 


verity. 
got it it knocked, 
resting o on y rour 
body co 
a Scie 
Witness a 
the Centroni 
the Epson MX 
in 1981. 

And now, witness w 
happening to the MX 
the ProWriter comet! 
the foremost printer c of 
decade. 

SPEED 

MX-80: 80 cps, for 46 full 
per minute throughput. 
PROWRITER: 120 c cps, for 
63 full lines per minute 
throughput. 

GRAPHICS 

MX-80: Block | 

fine for things like b 
PROWRITER: Hehe -resolu- 
tion graphics features, fine 
for bar graphs, smooth curves, 
thin lines, intricate details, etc. 
PRINTING 

MxX-80: Dot matrix business 
quality. 

PROWRITER: Dot matrix 
correspondence quality, with 
incremental printing capability 
standard. 

FEED 

MX-80: Tractor feed standard; 
optional friction-feed kit for 
about $75 extra. 
PROWRITER: Both tractor 
and friction feed standard. 
INTERFACE 

MX-80: Parallel interface 
standard; optional serial 
interface for about $75 extra. 
PROWRITER: Available stan- 
dard—either parallel interface 
or parallel/serial interface. 


WARRANTY 

MX-80: 90 days, from Epson. 
PROWRITER: One full year, 
from Leading Edge. 

PRICE 

Heh, heh. 

Marketed Exclusively by Leading 
Edge Products, Inc., 225 Turnpike 
Street, Canton, Massachusetts 
02021. Call: toll-free 1-800-343-6833: 
or in Massachusetts call collect 
(617) 828-8150. Telex 951-624. 


LEADING 
EDGE. 


For a free poster of “Ace” 
(Prowriter's pilot/ doing his thing, 
please write us.